Estrogen inhibits cardiomyocyte hypertrophy in vitro. Antagonism of calcineurin-related hypertrophy through induction of MCIP1

Controlled ovarian stimulation leads to cardiovascular changes in patients undergoing in vitro fertilization

OBJECTIVE

To study hemodynamic changes along controlled ovarian stimulation in women undergoing in vitro fertilization.

STUDY DESIGN

Prospective observational cohort study conducted at Mother and Child Department of University Hospital Federico II, in Naples, Italy, between April 2021 and July 2022. Sixty-eight infertile patients undergoing controlled ovarian stimulation with gonadotropin, antagonist protocol and a fresh embryo transfer were included. Haemodynamic assessment was carried out using UltraSonic Cardiac Output Monitor at baseline (T1), estradiol peak (T2), fresh embryo-transfer day (T3). To evaluate relationships between quantitative variables and groups a Student T test for independent data was assessed. One-way analysis of variance (ANOVA) was used to determine the differences between the means of three time points (T1, T2 and T3) for quantitative variables. A mixed-model analysis of variance (ANOVA) was used to determine the differences between groups, among time points (T1, T2 and T3).

RESULTS

Sixty-eight patients were included. Significant differences over the three time points have been observed for CO (f = 3.78 l/min; p = 0.025), SVI (f = 3.56 ml/m2;p = 0.013), and RSVI (f = 4.84 dscm-5 m2; p = 0.009). No significant differences in trends have been found between beta hCG positive and beta hCG negative groups. There were no significant differences in maternal hemodynamic parameters at time-point T3 between patients treated with hCG 10,000 UI and with Triptorelin. Patients considered at increased risk of hyperstimulation reported a significant increase in SVI at baseline (26.9 ± 9.0 mL/m2 vs 21.9 ± 7.0 mL/m2; p = 0.010).

CONCLUSION

According to the results of our study, during controlled ovarian stimulation with antagonist protocol, patients undergo significant changes in maternal cardiovascular parameters over a very short period.

The impact of female sex hormones on cardiovascular disease: from mechanisms to hormone therapy

Cardiovascular disease remains the leading cause of mortality in women, yet it has not raised the awareness from the public. The pathogenesis of cardiovascular disease differs significantly between females and males concerning the effect of sex hormones. Estrogen and progestogen impact cardiovascular system through genomic and non-genomic effects. Before menopause, cardiovascular protective effects of estrogens have been well described. Progestogens were often used in combination with estrogens in hormone therapy. Fluctuations in sex hormone levels, particularly estrogen deficiency, were considered the specific risk factor in women's cardiovascular disease. However, considerable heterogeneity in the impact of hormone therapy was observed in clinical trials. The heterogeneity is likely closely associated with factors such as the initial time, administration route, dosage, and formulation of hormone therapy. This review will delve into the pathogenesis and hormone therapy, summarizing the effect of female sex hormones on hypertension, pre-eclampsia, coronary heart disease, heart failure with preserved ejection fraction, and cardiovascular risk factors specific to women.

Differences in cardiac adaptation to exercise in male and female athletes assessed by noninvasive techniques: a state-of-the-art review

Athlete's heart is generally regarded as a physiological adaptation to regular training, with specific morphological and functional alterations in the cardiovascular system. Development of the noninvasive imaging techniques over the past several years enabled better assessment of cardiac remodeling in athletes, which may eventually mimic certain pathological conditions with the potential for sudden cardiac death, or disease progression. The current literature provides a compelling overview of the available methods that target the interrelation of prolonged exercise with cardiac structure and function. However, this data stems from scientific studies that included mostly male athletes. Despite the growing participation of females in competitive sport meetings, little is known about the long-term cardiac effects of repetitive training in this population. There are several factors-biochemical, physiological and psychological, that determine sex-dependent cardiac response. Herein, the aim of this review was to compare cardiac adaptation to endurance exercise in male and female athletes with the use of electrocardiographic, echocardiographic, and biochemical examination, to determine the sex-specific phenotypes, and to improve the healthcare providers' awareness of cardiac remodeling in athletes. Finally, we discuss the possible exercise-induced alternations that should arouse suspicion of pathology and be further evaluated.

Effects of aging and endurance exercise training on cardiorespiratory fitness and cardiac structure and function in healthy midlife and older women

Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality in women in developed societies. Unfavorable structural and functional adaptations within the heart and central blood vessels with sedentary aging in women can act as the substrate for the development of debilitating CVD conditions such as heart failure with preserved ejection fraction (HFpEF). The large decline in cardiorespiratory fitness, as indicated by maximal or peak oxygen uptake (V̇o2max and V̇o2peak, respectively), that occurs in women as they age significantly affects their health and chronic disease status, as well as the risk of cardiovascular and all-cause mortality. Midlife and older women who have performed structured endurance exercise training for several years or decades of their adult lives exhibit a V̇o2max and cardiac and vascular structure and function that are on par or even superior to much younger sedentary women. Therefore, regular endurance exercise training appears to be an effective preventative strategy for mitigating the adverse physiological cardiovascular adaptations associated with sedentary aging in women. Herein, we narratively describe the aging and short- and long-term endurance exercise training adaptations in V̇o2max, cardiac structure, and left ventricular systolic and diastolic function at rest and exercise in midlife and older women. The role of circulating estrogens on cardiac structure and function is described for consideration in the timing of exercise interventions to maximize beneficial adaptations. Current research gaps and potential areas for future investigation to advance our understanding in this critical knowledge area are highlighted.

The emerging role of estrogen's non-nuclear signaling in the cardiovascular disease

Sexual dimorphism exists in the epidemiology of cardiovascular disease (CVD), which indicates the involvement of sexual hormones in the pathophysiology of CVD. In particular, ample evidence has demonstrated estrogen's protective effect on the cardiovascular system. While estrogen receptors, bound to estrogen, act as a transcription factor which regulates gene expressions by binding to the specific DNA sequence, a subpopulation of estrogen receptors localized at the plasma membrane induces activation of intracellular signaling, called "non-nuclear signaling" or "membrane-initiated steroid signaling of estrogen". Although the precise molecular mechanism of non-nuclear signaling as well as its physiological impact was unclear for a long time, recent development of genetically modified animal models and pathway-selective estrogen receptor stimulant bring new insights into this pathway. We review the published experimental studies on non-nuclear signaling of estrogen, and summarize its role in cardiovascular system, especially focusing on: (1) the molecular mechanism of non-nuclear signaling; (2) the design of genetically modified animals and pathway-selective stimulant of estrogen receptor.

Membrane Estrogen Receptor β Is Sufficient to Mitigate Cardiac Cell Pathology

Estrogen acting through estrogen receptor β (ERβ) has been shown to oppose the stimulation of cardiac myocytes and cardiac fibroblasts that results in cardiac hypertrophy and fibrosis. Previous work has implicated signal transduction from ERβ as being important to the function of estrogen in this regard. Here we address whether membrane ERβ is sufficient to oppose key mechanisms by which angiotensin II (AngII) stimulates cardiac cell pathology. To do this we first defined essential structural elements within ERβ that are necessary for membrane or nuclear localization in cells. We previously determined that cysteine 418 is the site of palmitoylation of ERβ that is required and sufficient for cell membrane localization in mice and is the same site in humans. Here we determined in Chinese hamster ovarian (CHO) cells, and mouse and rat myocytes and cardiac fibroblasts, the effect on multiple aspects of signal transduction by expressing wild-type (WT ) or a C418A-mutant ERβ. To test the importance of the nuclear receptor, we determined a 4-amino acid deletion in the E domain of ERβ that strongly blocked nuclear localization. Using these tools, we expressed WT and mutant ERβ constructs into cardiomyocytes and cardiac fibroblasts from ERβ-deleted mice. We determined the ability of estrogen to mitigate cell pathology stimulated by AngII and whether the membrane ERβ is necessary and sufficient.

Multiscale model of heart growth during pregnancy: integrating mechanical and hormonal signaling

Pregnancy stands at the interface of mechanics and biology. The growing fetus continuously loads the maternal organs as circulating hormone levels surge, leading to significant changes in mechanical and hormonal cues during pregnancy. In response, maternal soft tissues undergo remarkable growth and remodeling to support the mother and baby for a healthy pregnancy. We focus on the maternal left ventricle, which increases its cardiac output and mass during pregnancy. This study develops a multiscale cardiac growth model for pregnancy to understand how mechanical and hormonal cues interact to drive this growth process. We coupled a cell signaling network model that predicts cell-level hypertrophy in response to hormones and stretch to a compartmental model of the rat heart and circulation that predicts organ-level growth in response to hemodynamic changes. We calibrated this multiscale model to data from experimental volume overload and hormonal infusions of angiotensin 2 (AngII), estrogen (E2), and progesterone (P4). We then validated the model's ability to capture interactions between inputs by comparing model predictions against published observations for the combinations of VO + E2 and AngII + E2. Finally, we simulated pregnancy-induced changes in hormones and hemodynamics to predict heart growth during pregnancy. Our model produced growth consistent with experimental data. Overall, our analysis suggests that the rise in P4 during the first half of gestation is an important contributor to heart growth during pregnancy. We conclude with suggestions for future experimental studies that will provide a better understanding of how hormonal and mechanical cues interact to drive pregnancy-induced heart growth.

Sex Differences in Molecular Mechanisms of Cardiovascular Aging

Cardiovascular disease (CVD) is still the leading cause of illness and death in the Western world. Cardiovascular aging is a progressive modification occurring in cardiac and vascular morphology and physiology where increased endothelial dysfunction and arterial stiffness are observed, generally accompanied by increased systolic blood pressure and augmented pulse pressure. The effects of biological sex on cardiovascular pathophysiology have long been known. The incidence of hypertension is higher in men, and it increases in postmenopausal women. Premenopausal women are protected from CVD compared with age-matched men and this protective effect is lost with menopause, suggesting that sex-hormones influence blood pressure regulation. In parallel, the heart progressively remodels over the course of life and the pattern of cardiac remodeling also differs between the sexes. Lower autonomic tone, reduced baroreceptor response, and greater vascular function are observed in premenopausal women than men of similar age. However, postmenopausal women have stiffer arteries than their male counterparts. The biological mechanisms responsible for sex-related differences observed in cardiovascular aging are being unraveled over the last several decades. This review focuses on molecular mechanisms underlying the sex-differences of CVD in aging.

Evaluation of the Interaction of Sex Hormones and Cardiovascular Function and Health

Purpose of Review

Sex hormones drive development and function of reproductive organs or the development of secondary sex characteristics but their effects on the cardiovascular system are poorly understood. In this review, we identify the gaps in our understanding of the interaction between sex hormones and the cardiovascular system.

Recent Findings

Studies are progressively elucidating molecular functions of sex hormones in specific cell types in parallel with the initiation of crucial large randomized controlled trials aimed at improving therapies for cardiovascular diseases (CVDs) associated with aberrant levels of sex hormones.

Summary

In contrast with historical assumptions, we now understand that men and women show different symptoms and progression of CVDs. Abnormal levels of sex hormones pose an independent risk for CVD, which is apparent in conditions like Klinefelter syndrome, androgen insensitivity syndrome, and menopause. Moreover, sex hormone–based therapies remain understudied and may not be beneficial for cardiovascular health.

Estrogen inhibits endoplasmic reticulum stress and ameliorates myocardial ischemia/reperfusion injury in rats by upregulating SERCA2a

Background

The incidence of coronary heart disease (CHD) in premenopausal women is significantly lower than that of men of the same age, suggesting protective roles of estrogen for the cardiovascular system against CHD. This study aimed to confirm the protective effect of estrogen on myocardium during myocardial ischemia/reperfusion (MI/R) injury and explore the underlying mechanisms.

Methods

Neonatal rat cardiomyocytes and Sprague–Dawley rats were used in this study. Different groups were treated by bilateral ovariectomy, 17β-estradiol (E2), adenoviral infection, or siRNA transfection. The expression of sarcoplasmic reticulum Ca²⁺ ATPase pump (SERCA2a) and endoplasmic reticulum (ER) stress-related proteins were measured in each group to examine the effect of different E2 levels and determine the relationship between SERCA2a and ER stress. The cell apoptosis, myocardial infarction size, levels of apoptosis and serum cardiac troponin I, ejection fraction, calcium transient, and morphology changes of the myocardium and ER were examined to verify the effects of E2 on the myocardium.

Results

Bilateral ovariectomy resulted in reduced SERCA2a levels and more severe MI/R injury. E2 treatment increased SERCA2a expression. Both E2 treatment and exogenous SERCA2a overexpression decreased levels of ER stress-related proteins and alleviated myocardial damage. In contrast, SERCA2a knockdown exacerbated ER stress and myocardial damage. Addition of E2 after SERCA2a knockdown did not effectively inhibit ER stress or reduce myocardial injury.

Conclusions

Our data demonstrate that estrogen inhibits ER stress and attenuates MI/R injury by upregulating SERCA2a. These results provide a new potential target for therapeutic intervention and drug discovery in CHD.

Trpc6 Promotes Doxorubicin-Induced Cardiomyopathy in Male Mice With Pleiotropic Differences Between Males and Females

Background: Doxorubicin is a widely used and effective chemotherapy, but the major limiting side effect is cardiomyopathy which in some patients leads to congestive heart failure. Genetic variants in TRPC6 have been associated with the development of doxorubicin-induced cardiotoxicity, suggesting that TRPC6 may be a therapeutic target for cardioprotection in cancer patients. Methods: Assessment of Trpc6 deficiency to prevent doxorubicin-induced cardiac damage and function was conducted in male and female B6.129 and Trpc6 knock-out mice. Mice were treated with doxorubicin intraperitoneally every other day for a total of 6 injections (4 mg/kg/dose, cumulative dose 24 mg/kg). Cardiac damage was measured in heart sections by quantification of vacuolation and fibrosis, and in heart tissue by gene expression of Tnni3 and Myh7. Cardiac function was determined by echocardiography. Results: When treated with doxorubicin, male Trpc6-deficient mice showed improvement in markers of cardiac damage with significantly reduced vacuolation, fibrosis and Myh7 expression and increased Tnni3 expression in the heart compared to wild-type controls. Similarly, male Trpc6-deficient mice treated with doxorubicin had improved LVEF, fractional shortening, cardiac output and stroke volume. Female mice were less susceptible to doxorubicin-induced cardiac damage and functional changes than males, but Trpc6-deficient females had improved vacuolation with doxorubicin treatment. Sex differences were observed in wild-type and Trpc6-deficient mice in body-weight and expression of Trpc1, Trpc3 and Rcan1 in response to doxorubicin. Conclusions: Trpc6 promotes cardiac damage following treatment with doxorubicin resulting in cardiomyopathy in male mice. Female mice are less susceptible to cardiotoxicity with more robust ability to modulate other Trpc channels and Rcan1 expression.

A case study of a patient-centered reverse translational systems-based approach to understand adverse event profiles in drug development

Adverse drug reactions (ADRs) of targeted therapy drugs (TTDs) are frequently unexpected and long‐term toxicities detract from exceptional efficacy of new TTDs. In this proof‐of‐concept study, we explored how molecular causation involved in trastuzumab‐induced cardiotoxicity changes when trastuzumab was given in combination with doxorubicin, tamoxifen, paroxetine, or lapatinib. The data analytical platform Molecular Health Effect was utilized to map population ADR data from the US Food and Drug Administration (FDA) Adverse Event Reporting System to chemical and biological databases (such as UniProt and Reactome), for hypothesis generation regarding the underlying molecular mechanisms causing cardiotoxicity. Disproportionality analysis was used to assess the statistical relevance between adverse events of interest and molecular causation. Literature search was performed to compare the established hypotheses to published experimental findings. We found that the combination therapy of trastuzumab and doxorubicin may affect mitochondrial dysfunction in cardiomyocytes through different molecular pathways such as BCL‐X and PGC‐1α proteins, leading to a synergistic effect of cardiotoxicity. We found, on the other hand, that trastuzumab‐induced cardiotoxicity would be diminished by concomitant use of tamoxifen, paroxetine, and/or lapatinib. Tamoxifen and paroxetine may cause less cardiotoxicity through an increase in antioxidant activities, such as glutathione conjugation. Lapatinib may decrease the apoptotic effects in cardiomyocytes by altering the effects of trastuzumab on BCL‐X proteins. This patient‐centered systems‐based approach provides, based on the trastuzumab‐induced ADR cardiotoxicity, an example of how to apply reverse translation to investigate ADRs at the molecular pathway and target level to understand the causality and prevalence during drug development of novel therapeutics.

Sexual dimorphism in cardiac remodeling: the molecular mechanisms ruled by sex hormones in the heart

Heart failure (HF) is growing in prevalence, due to an increase in aging and comorbidities. Heart failure with reduced ejection fraction (HFrEF) is more common in men, whereas heart failure with preserved ejection fraction (HFpEF) has a higher prevalence in women. However, the reasons for these epidemiological trends are not clear yet. Since HFpEF affects mostly postmenopausal women, sex hormones should play a pivotal role in HFpEF development. Furthermore, for HFpEF, contrary to HFrEF, effective therapeutic approaches are missing. Interestingly, studies evidenced that some therapies can have better results in women than in HFpEF men, emphasizing the necessity of understanding these observations at a molecular level. Thus, herein, we review the molecular mechanisms of estrogen and androgen actions in the heart in physiological conditions and explain how its dysregulation can lead to disease development. This clarification is essential in the road for an effective personalized management of HF, particularly HFpEF, towards the development of sex-specific therapeutic approaches.

Sex Differences, Estrogen Metabolism and Signaling in the Development of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a complex and devastating disease with a poor long-term prognosis. While women are at increased risk for developing PAH, they exhibit superior right heart function and higher survival rates than men. Susceptibility to disease risk in PAH has been attributed, in part, to estrogen signaling. In contrast to potential pathological influences of estrogen in patients, studies of animal models reveal estrogen demonstrates protective effects in PAH. Consistent with this latter observation, an ovariectomy in female rats appears to aggravate the condition. This discrepancy between observations from patients and animal models is often called the "estrogen paradox." Further, the tissue-specific interactions between estrogen, its metabolites and receptors in PAH and right heart function remain complex; nonetheless, these relationships are essential to characterize to better understand PAH pathophysiology and to potentially develop novel therapeutic and curative targets. In this review, we explore estrogen-mediated mechanisms that may further explain this paradox by summarizing published literature related to: (1) the synthesis and catabolism of estrogen; (2) activity and functions of the various estrogen receptors; (3) the multiple modalities of estrogen signaling in cells; and (4) the role of estrogen and its diverse metabolites on the susceptibility to, and progression of, PAH as well as their impact on right heart function.

Sex-related differences in ventricular remodeling after myocardial infarction

The epidemiology, clinical features and outcome of myocardial infarction (MI) display significant differences between men and women. Prominent sex differences have also been suggested in left ventricular (LV) remodeling after MI. Ventricular remodeling refers to a deterioration of LV geometry and function often leading to heart failure (HF) development and an increased risk of adverse cardiovascular events. Women have a lower propensity to the acquisition of a spherical geometry and LV dysfunction. These differences can be attributed at least partially to a lower frequency of transmural infarction and smaller areas of microvascular obstruction in women, as well as to a less prominent activation of neuroendocrine systems and apoptotic, inflammatory and profibrotic pathways in women. Estrogens might play a role in this difference, which could partially persist even after the menopause because of a persisting intramyocardial synthesis of estrogens in women. Conversely, androgens may exert a detrimental influence. Future studies should better clarify sex differences in the predictors, clinical correlates, prognostic impact and disease mechanisms of remodeling, as well as the existence of sex-specific therapeutic targets. This research effort should hopefully allow to optimize the treatment of MI during the acute and post-acute phase, possibly through different therapeutic strategies in men and women, with the goal of reducing the risk of HF development and improving patient outcome.

The impact of sex and gender on heart-brain axis dysfunction: current concepts and novel perspectives

The heart-brain axis (HBA) recapitulates all the circuits that regulate bidirectional flow of communication between heart and brain. Several mechanisms may underlie the interdependent relationship involving heterogeneous tissues at rest and during specific target organ injury such as myocardial infarction, heart failure, arrhythmia, stroke, mood disorders, or dementia. In-depth translational studies of the HBA dysfunction under single-organ injury should include both male and female animals to develop sex- and gender-oriented prevention, diagnosis, and treatment strategies. Indeed, sex and gender are determining factors as females and males exhibit significant differences in terms of susceptibility to risk factors, age of onset, severity of symptoms, and outcome. Despite most studies having focused on the male population, we have conducted a careful appraisal of the literature investigating HBA in females. In particular, we have (i) analyzed sex-related heart and brain illnesses, (ii) recapitulated the most significant studies simultaneously conducted on cardio- and cerebro-vascular systems in female populations, and (iii) hypothesized future perspectives for the development of a gender-based approach to HBA dysfunction. Although sex- and gender-oriented research is at its infancy, the impact of sex on HBA dysfunction is opening unexpected new avenues for managing the health of female subjects exposed to risk of lifestyle multi-organ disease.

Estrogen Receptors: Therapeutic Perspectives for the Treatment of Cardiac Dysfunction after Myocardial Infarction

Estrogen receptors (ER) mediate functions beyond their endocrine roles, as modulation of cardiovascular, renal, and immune systems through anti-inflammatory and anti-apoptotic effects, preventing necrosis of cardiomyocytes and endothelial cells, and attenuating cardiac hypertrophy. Estradiol (E2) prevents cardiac dysfunction, increases nitric oxide synthesis, and reduces the proliferation of vascular cells, yielding protective effects, regardless of gender. Such actions are mediated by ER (ER-alpha (ERα), ER-beta (ERβ), or G protein-coupled ER (GPER)) through genomic or non-genomic pathways, which regulate cardiovascular function and prevent tissue remodeling. Despite the extensive knowledge on the cardioprotective effects of estrogen, clinical studies conducted on myocardial infarction (MI) and cardiovascular diseases still include favorable and unfavorable profiles. The purpose of this review is to provide up-to-date information regarding molecular, preclinical, and clinical aspects of cardiovascular E2 effects and ER modulation as a potential therapeutic target for the treatment of MI-induced cardiac dysfunction.

Computational models of cardiac hypertrophy

Cardiac hypertrophy, defined as an increase in mass of the heart, is a complex process driven by simultaneous changes in hemodynamics, mechanical stimuli, and hormonal inputs. It occurs not only during pre- and post-natal development but also in adults in response to exercise, pregnancy, and a range of cardiovascular diseases. One of the most exciting recent developments in the field of cardiac biomechanics is the advent of computational models that are able to accurately predict patterns of heart growth in many of these settings, particularly in cases where changes in mechanical loading of the heart play an import role. These emerging models may soon be capable of making patient-specific growth predictions that can be used to guide clinical interventions. Here, we review the history and current state of cardiac growth models and highlight three main limitations of current approaches with regard to future clinical application: their inability to predict the regression of heart growth after removal of a mechanical overload, inability to account for evolving hemodynamics, and inability to incorporate known growth effects of drugs and hormones on heart growth. Next, we outline growth mechanics approaches used in other fields of biomechanics and highlight some potential lessons for cardiac growth modeling. Finally, we propose a multiscale modeling approach for future studies that blends tissue-level growth models with cell-level signaling models to incorporate the effects of hormones in the context of pregnancy-induced heart growth.

Mechanisms by Which Membrane and Nuclear ER Alpha Inhibit Adipogenesis in Cells Isolated From Female Mice

Mesenchymal stem cells can differentiate into mature chondrocytes, osteoblasts, and adipocytes. Excessive and dysfunctional visceral adipocytes increase upon menopause and importantly contribute to altered metabolism in postmenopausal women. We previously showed both plasma membrane and nuclear estrogen receptors alpha (ERα) with endogenous estrogen are required to suppress adipogenesis in vivo. Here we determined mechanisms by which these liganded ER pools collaborate to inhibit the peroxisome proliferator-activated gamma (PPARγ) gene and subsequent progenitor differentiation. In 3T3-L1 pre-adipocytes and adipose-derived stem cells (ADSC), membrane ERα signaled through phosphatidylinositol 3-kinase (PI3K)-protein kinase B (AKT) to enhance ERα nuclear localization, importantly at the PPARγ gene promoter. AKT also increased overall abundance and recruitment of co-repressors GATA3, β-catenin, and TCF4 to the PPARγ promoter. Membrane ERα signaling additionally enhanced wingless-integrated (Wnt)1 and 10b expression. The components of the repressor complex were required for estrogen to inhibit rosiglitazone-induced differentiation of ADSC and 3T3-L1 cells to mature adipocytes. These mechanisms whereby ER cellular pools collaborate to inhibit gene expression limit progenitor differentiation to mature adipocytes.

Danshen (Salvia miltiorhiza) inhibits Leu27 IGF-II-induced hypertrophy in H9c2 cells

In this study, we used ICI 182 780 (ICI), an estrogen receptor (ER) antagonist, to investigate the estrogenic activity of Danshen, and to further explored whether Danshen extract can block Leu27IGF-II-induced hypertrophy in H9c2 cardiomyoblast cells. We first used an IGF-II analog Leu27IGF-II, which specifically activates IGF2R signaling cascades and induces H9c2 cardiomyoblast cell hypertrophy. However, Danshen extract completely inhibited Leu27IGF-II-induced cell size increase, ANP and BNP hypertrophic marker expression, and IGF2R induction. We also observed that Danshen extract inhibited calcineurin protein expression and NFAT3 nuclear translocation, leading to suppression of Leu27IGF-II-induced cardiac hypertrophy. Moreover, the anti-Leu27IGF-II-IGF2R signaling effect of Danshen was totally reversed by ICI, which suggest the cardio protective effect of Danshen is mediated through estrogen receptors. Our study suggests that, Danshen exerts estrogenic activity, and thus, it could be used as a selective ER modulator in IGFIIR induced hypertrophy model.

The Effect of Estrogen on Intracellular Ca2+ and Na+ Regulation in Heart Failure

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During the progression toward heart failure, indicators of in vivo whole-heart function suggest greater impairment in the absence of estrogen.

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At the single cardiac myocyte level, the absence of estrogen results in further reduction of Ca²⁺ transient amplitudes, further slowing of transient decay kinetics, less SR Ca²⁺ content, and a further increase in Ca²⁺ spark frequencies and spark-mediated SR leak compared with animals with normal estrus cycles.

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Cardiac myocyte Na⁺ regulation is also more disrupted in the absence of estrogen.

Contradictory findings of estrogen supplementation in cardiac disease highlight the need to investigate the involvement of estrogen in the progression of heart failure in an animal model that lacks traditional comorbidities. Heart failure was induced by aortic constriction (AC) in female guinea pigs. Selected AC animals were ovariectomized (ACOV), and a group of these received 17β-estradiol supplementation (ACOV+E). One hundred-fifty days post-AC surgery, left-ventricular myocytes were isolated, and their electrophysiology and Ca²⁺ and Na⁺ regulation were examined. Long-term absence of ovarian hormones exacerbates the decline in cardiac function during the progression to heart failure. Estrogen supplementation reverses these aggravating effects.

Estrogen-related mechanisms in sex differences of hypertension and target organ damage

Hypertension (HTN) is a primary risk factor for cardiovascular (CV) events, target organ damage (TOD), premature death and disability worldwide. The pathophysiology of HTN is complex and influenced by many factors including biological sex. Studies show that the prevalence of HTN is higher among adults aged 60 and over, highlighting the increase of HTN after menopause in women. Estrogen (E2) plays an important role in the development of systemic HTN and TOD, exerting several modulatory effects. The influence of E2 leads to alterations in mechanisms regulating the sympathetic nervous system, renin-angiotensin-aldosterone system, body mass, oxidative stress, endothelial function and salt sensitivity; all associated with a crucial inflammatory state and influenced by genetic factors, ultimately resulting in cardiac, vascular and renal damage in HTN. In the present article, we discuss the role of E2 in mechanisms accounting for the development of HTN and TOD in a sex-specific manner. The identification of targets with therapeutic potential would contribute to the development of more efficient treatments according to individual needs.

The importance of ST elevation in V2-4 ECG leads in athletes

BACKGROUND

Early repolarization in the anterior ECG leads (ERV_2-4) is considered to be a sign of right ventricular (RV) remodeling, but its etiology and importance are unclear.

METHODS

A total of 243 top-level endurance-trained athletes (ETA; 183 men and 60 women, weekly training hours: 15-20) and 120 leisure-time athletes (LTA; 71 men and 49 women, weekly training hours: 5-6) were investigated. The ERV_2-4 sign was evaluated concerning type of sport, gender, transthoracic echocardiographic parameters, and ECG changes, which can indicate elevated RV systolic pressure [left atrium enlargement (LAE), right atrium enlargement (RAE), RV conduction defect (RVcd)].

RESULTS

Stroke volume and left ventricular mass were higher in ETAs vs. LTAs in both genders (p < 0.01). Prevalence of the ERV_2-4 sign was significantly higher in men than in women [p = 0.000, odds ratio (OR) = 36.4] and in ETAs than in LTAs (p = 0.000). The highest ERV_2-4 prevalence appeared in the most highly trained triathlonists and canoe and kayak paddlers (OR = 13.8 and 5.2, respectively). Within the ETA group, the post-exercise LAE, RAE, and RVcd changes developed more frequently in cases with than without ERV_2-4 (LAE: men: p < 0.05, females: p < 0.005; RAE: men: p < 0.05, females: p < 0.005; RVcd: N.S.). These post-exercise appearing LAE, RAE, and RVcd are associated with the ERV_2-4 sign (OR = 4.0, 3.7, and 3.8, respectively).

CONCLUSIONS

According to these results, ERV_2-4 develops mainly in male ETAs due to long-lasting and repeated endurance training. The ERV_2-4 sign indicates RV's adaptation to maintain higher compensatory pulmonary pressure and flow during exercise but its danger regarding malignant arrhythmias is unclear.

Membrane-initiated estrogen signaling in prostate cancer: A route to epithelial-to-mesenchymal transition

The plasma membrane (PM) is considered as a major druggable site. More than 50% of the existing drugs target PM proteins. In the wake of emerging data indicating a key role of estrogens in prostate cancer (PCa) pathogenesis, the study was undertaken to explore whether the estrogen binding sites exist on the PM and if such sites are functionally relevant in PCa. Estradiol (E2) binding to the PM was detected in androgen-dependent (LNCaP), androgen-independent (PC3, DU145) PCa cell lines, nontumorigenic (RWPE1) prostate epithelial cell line, and rat prostate cells. Conventional estrogen receptors (nuclear estrogen receptors), known for their nuclear localization, were detected in the PM enriched extracts. This was indirectly confirmed by reduced localization of ERs on the PM of cells, silenced for the expression of their cognate genes. Further, unlike cell-permeable E2, stimulation with cell-impermeable estradiol (E2-BSA) did not induce proliferation in LNCaP cells. However, stimulation with E2-BSA led to alterations in the phosphorylation status of several kinases including GSK3 and AKT, along with the hyperphosphorylation of cytoskeletal proteins such as β-actin and cytokeratin 8 in LNCaP. This was accompanied by epithelial-to-mesenchymal (EMT) features such as increased migration and invasion; higher vimentin expression, and a concomitant decrease in the E-cadherin expression. These effects were not observed in RWPE1 cells. Interestingly, cell-permeable E2 failed to induce EMT in PCa cells. This in vitro study is the first to suggest that the PM-initiated estrogen signaling contributes to higher invasiveness in PCa cells. Plasma membrane ERs may act as novel targets for PCa therapeutics.

Female ClockΔ19/Δ19 mice are protected from the development of age-dependent cardiomyopathy

Aims

Circadian rhythms are important for healthy cardiovascular physiology and they are regulated by the molecular circadian mechanism. Previously, we showed that disruption of the circadian mechanism factor CLOCK in male ClockΔ19/Δ19 mice led to development of age-dependent cardiomyopathy. Here, we investigate the role of biological sex in protecting against heart disease in aging female ClockΔ19/Δ19 mice.

Methods and results

Female ClockΔ19/Δ19 mice are protected from the development of cardiomyopathy with age, as heart structure and function are similar to 18 months of age vs. female WT mice. We show that female ClockΔ19/Δ19 mice maintain normal glucose tolerance as compared with female WT. Tissue metabolic profiling revealed that aging female ClockΔ19/Δ19 mice maintain normal cardiac glucose uptake, whereas the male ClockΔ19/Δ19 mice have increased cardiac glucose uptake consistent with pathological remodelling. Shotgun lipidomics revealed differences in phospholipids that were sex and genotype specific, including cardiolipin CL76:11 that was increased and CL72:8 that was decreased in male ClockΔ19/Δ19 mice. Additionally, female ClockΔ19/Δ19 mice show increased activation of AKT signalling and preserved cytochrome c oxidase activity compared with male ClockΔ19/Δ19 mice, which can help to explain why they are protected from heart disease. To determine how this protection occurs in females even with the Clock mutation, we examined the effects of ovarian hormones. We show that ovarian hormones protect female ClockΔ19/Δ19 mice from heart disease as ovariectomized female ClockΔ19/Δ19 mice develop cardiac dilation, glucose intolerance and reduced cardiac cytochrome c oxidase; this phenotype is consistent with the age-dependent decline observed in male ClockΔ19/Δ19 mice.

Conclusions

These data demonstrate that ovarian hormones protect female ClockΔ19/Δ19 mice from the development of age-dependent cardiomyopathy even though Clock function is disturbed. Understanding the interaction of biological sex and the circadian mechanism in cardiac growth, renewal and remodelling opens new doors for understanding and treating heart disease.

Non-genomic Effects of Estrogen on Cell Homeostasis and Remodeling With Special Focus on Cardiac Ischemia/Reperfusion Injury

This review takes into consideration the main mechanisms involved in cellular remodeling following an ischemic injury, with special focus on the possible role played by non-genomic estrogen effects. Sex differences have also been considered. In fact, cardiac ischemic events induce damage to different cellular components of the heart, such as cardiomyocytes, vascular cells, endothelial cells, and cardiac fibroblasts. The ability of the cardiovascular system to counteract an ischemic insult is orchestrated by these cell types and is carried out thanks to a number of complex molecular pathways, including genomic (slow) or non-genomic (fast) effects of estrogen. These pathways are probably responsible for differences observed between the two sexes. Literature suggests that male and female hearts, and, more in general, cardiovascular system cells, show significant differences in many parameters under both physiological and pathological conditions. In particular, many experimental studies dealing with sex differences in the cardiovascular system suggest a higher ability of females to respond to environmental insults in comparison with males. For instance, as cells from females are more effective in counteracting the ischemia/reperfusion injury if compared with males, a role for estrogen in this sex disparity has been hypothesized. However, the possible involvement of estrogen-dependent non-genomic effects on the cardiovascular system is still under debate. Further experimental studies, including sex-specific studies, are needed in order to shed further light on this matter.

Are the cardioprotective effects of the phytoestrogen resveratrol sex-dependent? 1

Cardiovascular disease (CVD) is the number one cause of death in both men and women. Younger women have a lower risk for CVD, but their risk increases considerably after menopause when estrogen levels decrease. The cardiovascular protective properties of estrogen are mediated through decreasing vascular inflammation and progression of atherosclerosis, decreasing endothelial cell damage by preventing apoptosis and anti-hypertrophic mechanisms. Estrogen also regulates glucose and lipid levels, which are 2 important risk factors for CVD. Resveratrol (RES), a cardioprotective polyphenolic compound, is classified as a phytoestrogen due its capacity to bind to and modulate estrogen receptor signalling. Due to its estrogen-like property, we speculate that the cardioprotective effects of RES treatment could be sex-dependent. Based on earlier reports and more recent data from our lab presented here, we found that RES treatment may have more favourable cardiovascular outcomes in females than in males. This review will discuss estrogen- and phytoestrogen-mediated cardioprotection, with a specific focus on sex-dependent effects reported in preclinical and clinical studies.

Estrogen receptor beta maintains expression of KLF15 to prevent cardiac myocyte hypertrophy in female rodents

Maintaining a healthy, anti-hypertrophic state in the heart prevents progression to cardiac failure. In humans, angiotensin II (AngII) indirectly and directly stimulates hypertrophy and progression, while estrogens acting through estrogen receptor beta (ERβ) inhibit these AngII actions. The KLF15 transcription factor has been purported to provide anti-hypertrophic action. In cultured neonatal rat cardiomyocytes, we found AngII inhibited KLF1 expression and nuclear localization, substantially prevented by estradiol (E2) or β-LGND2 (β-LGND2), an ERβ agonist. AngII stimulation of transforming growth factor beta expression in the myocytes activated p38α kinase via TAK1 kinase, inhibiting KLF15 expression. All was comparably reduced by E2 or β-LGND2. Knockdown of KLF15 in the myocytes induced myocyte hypertrophy and limited the anti-hypertrophic actions of E2 and β-LGND2. Key aspects were confirmed in an in-vivo model of cardiac hypertrophy. Our findings define additional anti-hypertrophic effects of ERβ supporting testing specific receptor agonists in humans to prevent progression of cardiac disease.

17β-Estradiol and/or estrogen receptor alpha signaling blocks protein phosphatase 1 mediated ISO induced cardiac hypertrophy

Earlier studies have shown that estrogen possess protective function against the development of pathological cardiac hypertrophy. However, the molecular mechanisms of estrogens (E2) protective effect are poorly understood. Additionally, abnormal activation of β-adrenergic signaling have been implicated in the development of pathological cardiac remodeling. However, the role of serine/threonine protein phosphatase 1 (PP1) in pathological cardiac remodeling under the influence of β-adrenergic signaling have been sparsely investigated. In this study, we assessed the downstream effects of abnormal activation of PP1 upon isoproterenol (ISO) induced pathological cardiac changes. We found that pre-treatment of 17β-estradiol (E2), tet-on estrogen receptor-α, or both significantly inhibited ISO-induced increase in cell size, hypertrophy marker gene expression and cytosolic calcium accumulation in H9c2 cells. Additionally, treatment with estrogen receptor inhibitor (ICI) reversed those effects, implicating role of E2 in inhibiting pathological cardiac remodeling. However, specific inhibition of ERα using melatonin, reduced ISO-induced PP1c expression and enhanced the level of ser-16 phosphorylated phospholamban (PLB), responsible for regulation of sarcoplasmic reticulum Ca²⁺-ATPase (SERCA) activity. Furthermore, hypertrophic effect caused by overexpression of PP1cα was reduced by treatment with specific inhibitor of ERα. Collectively, we found that estrogen and estrogen receptor-α have protective effect against pathological cardiac changes by suppressing PP1 expression and its downstream signaling pathway, which further needs to be elucidated.

Membrane estrogen receptors signal to determine transcription factor function

Estrogen receptors (ER) alpha and beta as well as many other steroid receptors are found both within the nucleus and outside the nucleus. This includes extra-nuclear receptors in many organelles, including mitochondria, endoplasmic reticulum, cytosolic endosomes, and membrane lipid rafts, such as caveolae. The functions of these receptors in the various extra-nuclear cell organelles are not well described, but progress for understanding steroid receptor signaling from the membrane has advanced. In this Review I will discuss the enlarging role of membrane ER signaling to the expression, cell localization, and function of transcription factors that are essential to mediate cell physiology or pathophysiology in many organs.

Endothelin-1-induced hypertrophic alterations and heme oxygenase-1 expression in cardiomyoblasts are counteracted by beta estradiol: in vitro and in vivo studies

Endothelin-1 (ET-1), a potent vasoconstrictor normally active in maintaining vascular tone, may mediate significant pathogenic effects, contributing to several serious diseases when aberrantly expressed or regulated. The present study evaluates the capacity of ET-1 to affect endothelin-1-associated hypertrophic activity and decreased expression of heme oxygenase-1 by H9c2 rat cardiomyoblasts in vitro, corresponding to in vivo processes underlying cardiovascular diseases (CVDs). Beta estradiol (β-E) is tested for its capacity to alter the effects of ET-1. H9c2 cells, cultured 48 h, were stimulated with 100-10,000 nM of ET-1 and evaluated for changes in cell size, cell viability, and expression of the cytoprotective heat shock protein heme oxygenase-1 (HO-1), with 200 nM of β-E included in selected cultures to evaluate its effect on ET-1-mediated changes. The application of 100 to 10,000 nM of ET-1 resulted in a significant increase in average cell size and decreases in both cell viability and HO-1 protein content (p < 0.05). Moreover, 200 nM of β-E was observed to significantly counteract these effects by cardiomyoblasts stimulated with 1000 nM of ET-1 (p < 0.05). Sprague-Dawley rats treated intravenously with 1000 ng/kg of ET-1 demonstrated reduced HO-1 expression in peripheral blood and left ventricular tissue, which was counteracted by injection of 200 ng/kg β-E-demonstrating a possible correspondence between in vitro and in vivo effects. An outcome of particular value for clinical use of β-E, in the management of cardiac hypertrophy, is the observed capacity of the drug to abate ET-1-mediated suppression of HO-1 expression. It has been previously demonstrated that HO-1 inducers exhibit potent cardioprotective properties, thus offering the promise of combining them with β-E, allowing lower effective dosage of the drug and concomitantly lower adverse side effects associated with its clinical use. Major findings of this investigation are that pretreatment of cardiomyoblasts with β-E inhibited their hypertrophic response to ET-1 and counteracts the decrease of cell viability. These effects were associated with a restoration of HO-1 protein expression in both under in vitro and in vivo conditions.

Cardiac Hypertrophy and Brain Natriuretic Peptide Levels in an Ovariectomized Rat Model Fed a High-Fat Diet

BACKGROUND Heart failure in women increases around the time of menopause when high-fat diets may result in obesity. The heart produces brain natriuretic peptide (BNP), also known as B-type natriuretic peptide. This aims of this study were to assess cardiac hypertrophy and BNP levels in ovariectomized rats fed a high-fat diet. MATERIAL AND METHODS Forty-eight female Wistar rats were divided into four groups: sham-operated rats fed a control diet (SC) (n=12); ovariectomized rats fed a control diet (OC) (n=12); sham-operated rats fed a high-fat diet (SF) (n=12); and ovariectomized rats fed a high-fat diet (OF) (n=12). Body weight and blood pressure were measured weekly for 24 weeks. Rats were then euthanized, and plasma samples and heart tissue were studied for gene expression, hydroxyproline levels, and histological examination. RESULTS A high-fat diet and ovariectomy (group OF) increased the weight body and the systolic blood pressure after three months and five months, respectively. Cardiomyocyte hypertrophy was associated with increased expression of ventricular BNP, decreased natriuretic peptide receptor (NPR)-A and increased levels of hydroxyproline and transforming growth factor (TGF)-β. The plasma levels of BNP and estradiol were inversely correlated; expression of estrogen receptor (ER)β and ERα were reduced. CONCLUSIONS The findings of this study showed that, in the ovariectomized rats fed a high-fat diet, the BNP-NPR-A receptor complex was involved in cardiac remodeling. BNP may be a marker of cardiac hypertrophy in this animal model.

RCAN1 in the inverse association between Alzheimer's disease and cancer

The inverse association between Alzheimer’s disease (AD) and cancer has been reported in several population-based studies although both of them are age-related disorders. However, molecular mechanisms of the inverse association remain elusive. Increased expression of regulator of calcineurin 1 (RCAN1) promotes the pathogenesis of AD, while it suppresses cancer growth and progression in many types of cancer. Moreover, aberrant RCAN1 expression is detected in both AD and various types of cancer. It suggests that RCAN1 may play a key role in the inverse association between AD and cancer. In this article, we aim to review the role of RCAN1 in the inverse association and discuss underlying mechanisms, providing an insight into developing a novel approach to treat AD and cancer.

Estrogen regulates spatially distinct cardiac mitochondrial subpopulations

Increased susceptibility to permeability transition pore (mPTP) is a significant concern to decreased cardiac performance in postmenopausal females. The goal of this study was to assess the effects of estrogen deficiency on the two spatially distinct mitochondrial subpopulations from left ventricle: subsarcolemmal mitochondria (SSM) and intermyofibrillar mitochondria (IFM) based on: morphology, membrane potential, oxidative phosphorylation, mPTP and reactive oxygen species production. Female rats (8weeks old) that underwent bilateral ovariectomy were randomly assigned to receive daily treatment with placebo (OVX), estrogen replacement (OVX+E2) and Sham for 60days. The yield for IFM was found higher in the OVX group and lower in the SSM. SSM internal complexity and size were higher in the OVX group, although membrane potential was not different. The maximal rate of mitochondrial respiration, states 3 and 4, using glutamate+malate as substrate, were higher in IFM and SSM from the OVX group. The respiratory control ratio (RCR - state3/state 4), was not different in both SSM and IFM with glutamate+malate. The ADP:O ratio was found lower in IFM and SSM from OVX compared to Sham. When pyruvate was used, state 3 was found unchanged in both IFM and SSM, state 4 was greater in IFM from OVX rats compared to Sham and the ADP/O ratio was decreased. The RCR was unchanged in both subpopulations. The IFM from OVX rats presented a lower Ca²⁺retention capacity compared to Sham, however, the SSM remained unchanged. Hydrogen peroxide formation was found increased in the IFM from OVX animals with glutamate+malate and rotenone+succinate as substrates. The SSM showed increased ROS production only with rotenone+succinate. Western blot analyzes showed decreased levels of PGC-1α and NRF-1 in the OVX group. Estrogen replacement was able to restore most of the alterations induced by ovariectomy. In conclusion, our data shows that estrogen deficiency has distinct effects on the two spatially distinct mitochondrial subpopulations in oxidative phosphorylation, morphology, calcium retention capacity and ROS production.

E2/ER β Enhances Calcineurin Protein Degradation and PI3K/Akt/MDM2 Signal Transduction to Inhibit ISO-Induced Myocardial Cell Apoptosis

Secretion of multifunctional estrogen and its receptor has been widely considered as the reason for markedly higher frequency of heart disease in men than in women. 17β-Estradiol (E2), for instance, has been reported to prevent development of cardiac apoptosis via activation of estrogen receptors (ERs). In addition, protein phosphatase such as protein phosphatase 1 (PP1) and calcineurin (PP2B) are also involved in cardiac hypertrophy and cell apoptosis signaling. However, the mechanism by which E2/ERβ suppresses apoptosis is not fully understood, and the role of protein phosphatase in E2/ERβ action also needs further investigation. In this study, we observed that E2/ERβ inhibited isoproterenol (ISO)-induced myocardial cell apoptosis, cytochrome c release and downstream apoptotic markers. Moreover, we found that E2/ERβ blocks ISO-induced apoptosis in H9c2 cells through the enhancement of calcineurin protein degradation through PI3K/Akt/MDM2 signaling pathway. Our results suggest that supplementation with estrogen and/or overexpression of estrogen receptor β gene may prove to be effective means to treat stress-induced myocardial damage.

Serum atrial natriuretic peptide: a suspected biomarker of breast cancer

Aim of the study

To assess serum levels of ANP in breast cancer female patients and its relationship to metastasis and some clinical parameters among those patients.

Material and methods

One hundred breast cancer patients with and without metastasis along with 20 healthy closely matched controls, were enrolled in the present cross sectional study. Background: To assess the serum levels of atrial natriuretic peptide in breast cancer Serum levels of ANP were assessed using ELISA.

Results

Mean serum levels of ANP breast cancer patients (13.9 ±10.1 ng/ml) were significantly elevated compared to healthy control group (2.2 ±1.3 ng/ml) (p < 0.001). The metastatic breast cancer patients showed significant elevated ANP levels (17.1 ±8.9 ng/ml) compared to non-metastatic group (6.4 ±8.8 ng/ml) p < 0.001. Within the metastatic group significant difference was detected between de novo metastatic, under follow-up, under hormonal control and locally advanced group (p = 0.007).

Conclusions

This study showed significant elevated levels of ANP in the serum of metastatic breast cancer patients compared to non-metastatic patients. Within the metastatic group the lowest levels were detected in metastatic breast Cancer under hormonal treatment either tamoxifen or aromatase inhibitor.

Nuclear receptors outside the nucleus: extranuclear signalling by steroid receptors

Steroid hormone receptors mediate numerous crucial biological processes and are classically thought to function as transcriptional regulators in the nucleus. However, it has been known for more than 50 years that steroids evoke rapid responses in many organs that cannot be explained by gene regulation. Mounting evidence indicates that most steroid receptors in fact exist in extranuclear cellular pools, including at the plasma membrane. This latter pool, when engaged by a steroid ligand, rapidly activates signals that affect various aspects of cellular biology. Research into the mechanisms of signalling instigated by extranuclear steroid receptor pools and how this extranuclear signalling is integrated with responses elicited by nuclear receptor pools provides novel understanding of steroid hormone signalling and its roles in health and disease.

ANGPTL2 activity in cardiac pathologies accelerates heart failure by perturbing cardiac function and energy metabolism

A cardioprotective response that alters ventricular contractility or promotes cardiomyocyte enlargement occurs with increased workload in conditions such as hypertension. When that response is excessive, pathological cardiac remodelling occurs, which can progress to heart failure, a leading cause of death worldwide. Mechanisms underlying this response are not fully understood. Here, we report that expression of angiopoietin-like protein 2 (ANGPTL2) increases in pathologically-remodeled hearts of mice and humans, while decreased cardiac ANGPTL2 expression occurs in physiological cardiac remodelling induced by endurance training in mice. Mice overexpressing ANGPTL2 in heart show cardiac dysfunction caused by both inactivation of AKT and sarco(endo)plasmic reticulum Ca²⁺-ATPase (SERCA)2a signalling and decreased myocardial energy metabolism. Conversely, Angptl2 knockout mice exhibit increased left ventricular contractility and upregulated AKT-SERCA2a signalling and energy metabolism. Finally, ANGPTL2-knockdown in mice subjected to pressure overload ameliorates cardiac dysfunction. Overall, these studies suggest that therapeutic ANGPTL2 suppression could antagonize development of heart failure.

Heart responds to increased workload by enlarging cardiomyocytes to preserve function, but in pathologies hypertrophy leads to heart failure. Here the authors show that ANGPTL2 activity in the heart is critical for determining beneficial vs. pathological hypertrophy via its effect on AKT-SERCA2a signaling and myocardial energy.

Cell-selective arrhythmia ablation for photomodulation of heart rhythm

Heart disease, a leading cause of death in the developed world, is overwhelmingly correlated with arrhythmias, where heart muscle cells, myocytes, beat abnormally. Cardiac arrhythmias are usually managed by electric shock intervention, antiarrhythmic drugs, surgery, and/or catheter ablation. Despite recent improvements in techniques, ablation procedures are still limited by the risk of complications from unwanted cellular damage, caused by the nonspecific delivery of ablative energy to all heart cell types. We describe an engineered nanoparticle containing a cardiac-targeting peptide (CTP) and a photosensitizer, chlorin e6 (Ce6), for specific delivery to myocytes. Specificity was confirmed in vitro using adult rat heart cell and human stem cell-derived cardiomyocyte and fibroblast cocultures. In vivo, the CTP-Ce6 nanoparticles were injected intravenously into rats and, upon laser illumination of the heart, induced localized, myocyte-specific ablation with 85% efficiency, restoring sinus rhythm without collateral damage to other cell types in the heart, such as fibroblasts. In both sheep and rat hearts ex vivo, upon perfusion of CTP-Ce6 particles, laser illumination led to the formation of a complete electrical block at the ablated region and restored the physiological rhythm of the heart. This nano-based, cell-targeted approach could improve ablative technologies for patients with arrhythmias by reducing currently encountered complications.

Rapid steroid hormone actions via membrane receptors

Steroid hormones regulate a wide variety of physiological and developmental functions. Traditional steroid hormone signaling acts through nuclear and cytosolic receptors, altering gene transcription and subsequently regulating cellular activity. This is particularly important in hormonally-responsive cancers, where therapies that target classical steroid hormone receptors have become clinical staples in the treatment and management of disease. Much progress has been made in the last decade in detecting novel receptors and elucidating their mechanisms, particularly their rapid signaling effects and subsequent impact on tumorigenesis. Many of these receptors are membrane-bound and lack DNA-binding sites, functionally separating them from their classical cytosolic receptor counterparts. Membrane-bound receptors have been implicated in a number of pathways that disrupt the cell cycle and impact tumorigenesis. Among these are pathways that involve phospholipase D, phospholipase C, and phosphoinositide-3 kinase. The crosstalk between these pathways has been shown to affect apoptosis and proliferation in cardiac cells, osteoblasts, and chondrocytes as well as cancer cells. This review focuses on rapid signaling by 17β-estradiol and 1α,25-dihydroxy vitamin D3 to examine the integrated actions of classical and rapid steroid signaling pathways both in contrast to each other and in concert with other rapid signaling pathways. This new approach lends insight into rapid signaling by steroid hormones and its potential for use in targeted drug therapies that maximize the benefits of traditional steroid hormone-directed therapies while mitigating their less desirable effects.

The Expanding Complexity of Estrogen Receptor Signaling in the Cardiovascular System

Estrogen has important effects on cardiovascular function including regulation of vascular function, blood pressure, endothelial relaxation, and the development of hypertrophy and cardioprotection. However, the mechanisms by which estrogen mediates these effects are still poorly understood. As detailed in this review, estrogen can regulate transcription by binding to 2 nuclear receptors, ERα and ERβ, which differentially regulate gene transcription. ERα and ERβ regulation of gene transcription is further modulated by tissue-specific coactivators and corepressors. Estrogen can bind to ERα and ERβ localized at the plasma membrane as well as G-protein-coupled estrogen receptor to initiate membrane delimited signaling, which enhances kinase signaling pathways that can have acute and long-term effects. The kinase signaling pathways can also mediate transcriptional changes and can synergize with the ER to regulate cell function. This review will summarize the beneficial effects of estrogen in protecting the cardiovascular system through ER-dependent mechanisms with an emphasis on the role of the recently described ER membrane signaling mechanisms.

Membrane and nuclear estrogen receptor α collaborate to suppress adipogenesis but not triglyceride content

Estrogen and estrogen receptor (ER)-α suppress visceral fat development through actions in several organs via unclear mechanisms that we sought to identify. Using mice that express only nuclear ER-α [nuclear-only ER-α (NOER) mice] or plasma membrane ER-α [membrane-only ER-α (MOER) mice], we found that 10-wk-old mice that lacked either receptor pool showed extensive abdominal visceral fat deposition and weight gain compared with wild-type (WT) mice. Differentiation of cultured bone marrow stem cells (BMSCs) into the adipocyte lineage was suppressed by 17-β-estradiol (E2) in WT female mice but not in NOER or MOER mice. This finding correlated with E2 inhibition of prominent differentiation genes in WT BMSCs. In contrast, triglyceride content in differentiated BMSCs or 3T3-L1 cells was suppressed as a result of membrane ER-α signaling through several kinases to inhibit carbohydrate response element-binding protein-α and -β. We concluded that extranuclear and nuclear ER-α collaborate to suppress adipocyte development, but inhibition of lipid synthesis in mature cells does not involve nuclear ER-α.

Extranuclear steroid receptors are essential for steroid hormone actions

Steroid hormones are produced throughout the phylogenetic tree, from plants to mammals. In the past 40 years, steroid receptors localized to the nucleus have been recognized as being important to mediating steroid action in many organs. This action mainly arises from the regulation of key genes that are important for organ development and function. These include but are not limited to genes influencing the reproductive tract, mammary glands, bone, brain, fat differentiation, pituitary hormone regulation, and metabolic effects in many organs. Unfortunately, steroids also promote the development of hormone-responsive cancers, including breast, uterus, and prostate cancer. It has also been shown that steroid receptors exist outside the nucleus in many organs and cells, with unclear impact for normal development, health, and disease. This review describes the evidence from many laboratories that these receptors exist and function with nuclear receptors to provide the full impact of all steroid hormones.

Statement on pregnancy in pulmonary hypertension from the Pulmonary Vascular Research Institute

Pregnancy outcomes in patients with pulmonary hypertension remain poor despite advanced therapies. Although consensus guidelines recommend against pregnancy in pulmonary hypertension, it may nonetheless occasionally occur. This guideline document sought to discuss the state of knowledge of pregnancy effects on pulmonary vascular disease and to define usual practice in avoidance of pregnancy and pregnancy management. This guideline is based on systematic review of peer-reviewed, published literature identified with MEDLINE. The strength of the literature was graded, and when it was inadequate to support high-level recommendations, consensus-based recommendations were formed according to prespecified criteria. There was no literature that met standards for high-level recommendations for pregnancy management in pulmonary hypertension. We drafted 38 consensus-based recommendations on pregnancy avoidance and management. Further, we identified the current state of knowledge on the effects of sex hormones during pregnancy on the pulmonary vasculature and right heart and suggested areas for future study. There is currently limited evidence-based knowledge about both the basic molecular effects of sex hormones and pregnancy on the pulmonary vasculature and the best practices in contraception and pregnancy management in pulmonary hypertension. We have drafted 38 consensus-based recommendations to guide clinicians in these challenging topics, but further research is needed in this area to define best practices and improve patient outcomes.

Overlapping nongenomic and genomic actions of thyroid hormone and steroids

The genomic actions of thyroid hormone and steroids depend upon primary interactions of the hormones with their specific nuclear receptor proteins. Formation of nuclear co-activator or co-repressor complexes involving the liganded receptors subsequently result in transcriptional events-either activation or suppression-at genes that are specific targets of thyroid hormone or steroids. Nongenomic actions of thyroid hormone and steroids are in contrast initiated at binding sites on the plasma membrane or in cytoplasm or organelles and do not primarily require formation of intranuclear receptor protein-hormone complexes. Importantly, hormonal actions that begin nongenomically outside the nucleus often culminate in changes in nuclear transcriptional events that are regulated by both traditional intranuclear receptors as well as other nuclear transcription factors. In the case of thyroid hormone, the extranuclear receptor can be the classical "nuclear" thyroid receptor (TR), a TR isoform, or integrin αvβ3. In the case of steroid hormones, the membrane receptor is usually, but not always, the classical "nuclear" steroid receptor. This concept defines the paradigm of overlapping nongenomic and genomic hormone mechanisms of action. Here we review some examples of how extranuclear signaling by thyroid hormone and by estrogens and androgens modulates intranuclear hormone signaling to regulate a number of vital biological processes both in normal physiology and in cancer progression. We also point out that nongenomic actions of thyroid hormone may mimic effects of estrogen in certain tumors.

The different role of sex hormones on female cardiovascular physiology and function: not only oestrogens

Human response to different physiologic stimuli and cardiovascular (CV) adaptation to various pathologies seem to be gender specific. Sex-steroid hormones have been postulated as the major contributors towards these sex-related differences. This review will discuss current evidence on gender differences in CV function and remodelling, and will present the different role of the principal sex-steroid hormones on female heart. Starting from a review of sex hormones synthesis, receptors and CV signalling, we will summarize the current knowledge concerning the role of sex hormones on the regulation of our daily activities throughout the life, via the modulation of autonomic nervous system, excitation-contraction coupling pathway and ion channels activity. Many unresolved questions remain even if oestrogen effects on myocardial remodelling and function have been extensively studied. So this work will focus attention also on the controversial and complex relationship existing between androgens, progesterone and female heart.

Hormone therapy with tamoxifen reduces plasma levels of NT-B-type natriuretic peptide but does not change ventricular ejection fraction after chemotherapy in women with breast cancer

The objective of this study was to evaluate the effect of tamoxifen on the plasma concentration of NT-pro-B-type natriuretic peptide (NT-proBNP) in women undergoing chemotherapy for breast cancer and to correlate changes in NT-proBNP with the left ventricular ejection fraction (LVEF). Over a period of 12 months, we followed 60 women with a diagnosis of breast cancer. The patients were separated into a group that received only chemotherapy (n=23), a group that received chemotherapy + tamoxifen (n=21), and a group that received only tamoxifen (n=16). Plasma levels of NT-proBNP were assessed at 0 (T0), 6 (T6), and 12 (T12) months of treatment, and echocardiography data were assessed at T0 and T12. Plasma NT-proBNP levels were increased in the chemotherapy-only group at T6 and T12, whereas elevated NT-proBNP levels were only found at T6 in the chemotherapy + tamoxifen group. At T12, the chemotherapy + tamoxifen group exhibited a significant reduction in the peptide to levels similar to the group that received tamoxifen alone. The chemotherapy-only group exhibited a significant decrease in LVEF at T12, whereas the chemotherapy + tamoxifen and tamoxifen-only groups maintained levels similar to those at the beginning of treatment. Treatment with tamoxifen for 6 months after chemotherapy significantly reduced the plasma levels of NT-proBNP and did not change LVEF in women with breast cancer.

Extranuclear estrogen receptor's roles in physiology: lessons from mouse models

Steroid receptors exist and function in multiple compartments of cells in most organs. Although the functions and nature of some of these receptors is being defined, important aspects of receptor localization and signaling to physiology and pathophysiology have been identified. In particular, extranuclear sex steroid receptors have been found in many normal cells and in epithelial tumors, where they enact signal transduction that impacts both nongenomic and genomic functions. Here, I focus on the progress made in understanding the roles of extranuclear estrogen receptors (ER) in physiology and pathophysiology. Extranuclear ER serve as a model to selectively intervene with novel receptor reagents to prevent or limit disease progression. Recent novel mouse models and membrane ER-selective agonists also provide a better understanding of receptor pool cross-talk that results in the overall integrative actions of sex steroids.

Significant role of female sex hormones in cardiac myofilament activation in angiotensin II-mediated hypertensive rats

Ovariectomy leads to suppression of cardiac myofilament activation in healthy rats implicating the physiological essence of female sex hormones on myocardial contraction. However, the possible function of these hormones during pathologically induced myofilament adaptation is not known. In this study, sham-operated and ovariectomized female rats were chronically exposed to angiotensin II (AII), which has been shown to cause myocardial adaptation. In the shams, AII induced cardiac adaptation by increasing myofilament Ca(2+) sensitivity. Interestingly, this hypersensitivity was further enhanced in AII-infused ovariectomized rats. Ovariectomy increased the phosphorylation levels of cardiac tropomyosin, which may underlie the mechanism of hypersensitivity. On the other hand, AII infusion did not alter maximal tension that was suppressed after ovariectomy. This finding coincided with a comparable increase in β-isoform of myosin heavy chains in both ovariectomized groups. Together, it is conceivable that female sex hormones serve as predominant factors that regulate cardiac myofilament activation. Furthermore, they may prevent stress-induced myofilament maladaptation.