Role of β-Adrenergic Receptors and Estrogen in Cardiac Repair after Myocardial Infarction: An Overview

Targeting the E Prostanoid Receptor EP4 Mitigates Cardiac Fibrosis Induced by β-Adrenergic Activation

Sustained β-adrenergic activation induces cardiac fibrosis characterized by excessive deposition of extracellular matrix (ECM). Prostaglandin E2 (PGE2) receptor EP4 is essential for cardiovascular homeostasis. This study aims to investigate the roles of cardiomyocyte (CM) and cardiac fibroblast (CF) EP4 in isoproterenol (ISO)-induced cardiac fibrosis. By crossing the EP4f/f mice with α-MyHC-Cre or S100A4-Cre mice, this work obtains the CM-EP4 knockout (EP4f/f-α-MyHCCre+) or CF-EP4 knockout (EP4f/f-S100A4Cre+) mice. The mice of both genders are subcutaneously injected with ISO (5 mg kg-1 day-1) for 7 days. Compared to the control mice, both EP4f/f-α-MyHCCre+ and EP4f/f-S100A4Cre+ mice show a significant improvement in cardiac diastolic function and fibrosis as assessed by echocardiography and histological staining, respectively. In the CMs, inhibition of EP4 suppresses ISO-induced TGF-β1 expression via blocking the cAMP/PKA pathway. In the CFs, inhibition of EP4 reversed TGF-β1-triggers production of ECM via preventing the formation of the TGF-β1/TGF-β receptor complex and blocks CF proliferation via suppressing the ERK1/2 pathway. Furthermore, double knockout of the CM- and CF-EP4 or administration of EP4 antagonist, grapiprant, markedly improves ISO-induced cardiac diastolic dysfunction and fibrosis. Collectively, this study demonstrates that both CM-EP4 and CF-EP4 contribute to β-adrenergic activation-induced cardiac fibrosis. Targeting EP4 may offer a novel therapeutic approach for cardiac fibrosis.

Underpinnings of Heart Failure With Preserved Ejection Fraction in Women - From Prevention to Improving Function. A Co-publication With the American Journal of Preventive Cardiology and the Journal of Cardiac Failure

Heart failure with preserved ejection fraction (HFpEF) represents a major clinical challenge with rising global prevalence. Women have a nearly double lifetime risk of developing HFpEF compared to heart failure with reduced ejection fraction (HFrEF). In HFpEF, sex differences emerge both in how traditional cardiovascular risk factors (such as hypertension, obesity, and diabetes) affect cardiac function and through distinct pathophysiological mechanisms triggered by sex-specific events like menopause and adverse pregnancy outcomes. These patterns influence not only disease development, but also therapeutic responses, necessitating sex-specific approaches to treatment. This review aims to synthesize existing knowledge regarding HFpEF in women including traditional and sex-specific risk factors, pathophysiology, presentation, and therapies, while outlining important knowledge gaps that warrant further investigation. The impact of HFpEF spans a woman's entire lifespan, requiring prevention and management strategies tailored to different life stages. While understanding of sex-based differences in HFpEF has improved, significant knowledge gaps persist. Through examination of current evidence and challenges, this review highlights promising opportunities for innovative research, therapeutic development, and clinical care approaches that could transform the management of HFpEF in women.

Metoprolol disrupts inflammatory response of human cardiomyocytes via β-arrestin2 biased agonism and NF-κB signaling modulation

AIMS

Recent evidence supports non-class cardioprotective effects of metoprolol against neutrophil-mediated ischemia-reperfusion injury during exacerbated inflammation. Whether metoprolol exerts direct anti-inflammatory effect on cardiomyocytes is unknown. Accordingly, we aimed to investigate the direct anti-inflammatory effects of metoprolol in a cellular model of human induced pluripotent stem cell-derived cardiomyocytes (hiCMs) and to explore the role of β-arrestin2 (β-ARR2) biased agonism signaling pathway.

METHODS AND RESULTS

hiCMs were treated with TNF-α for 24 h, followed by 4-hour treatment with metoprolol or esmolol. Electrical response of hiCMs to β1-selective blockade was assessed by microelectrode arrays technology. The effect on inflammatory and adhesion molecule expression was evaluated in wild-type and β-ARR2 silenced hiCMs. To silence β-ARR2 expression, hiCMs were transfected with a specific small interfering RNA targeting β-ARR2 mRNA and preventing its translation. TNF-α stimulation boosted the expression of IκB, NF-κB, IL1β, IL6, and VCAM1 in hiCMs. TNF-α-treated hiCMs showed similar physiological responses to metoprolol and esmolol, with no difference in field potential duration and beat period recorded. Adding metoprolol significantly decreased inflammatory response patterns in wild-type hiCMs by dampening TNF-α induced expression of NF-κB, IL1β, and IL6, but not in β-ARR2-knockout hiCMs. A similar response was not observed in presence of β1-selective blockade with esmolol.

CONCLUSIONS

Metoprolol exerts a non-class direct anti-inflammatory effect on hi-CMs. β1-selective blockade with metoprolol disrupts inflammatory responses induced by TNF-α and induces significant inhibition of NF-κB signaling cascade via β-ARR2 biased agonism. If confirmed at clinical level, metoprolol could be tested and repurposed to treat cardiac inflammatory disorders.

Sexual Dimorphism in Cardiometabolic Diseases: The Role of AMPK

Cardiovascular diseases (CVDs) are the leading cause of mortality and disability among both males and females. The risk of cardiovascular diseases is heightened by the presence of a risk factor cluster of metabolic syndrome, covering obesity and obesity-related cardiometabolic risk factors such as hypertension, glucose, and lipid metabolism dysregulation primarily. Sex hormones contribute to metabolic regulation and make women and men susceptible to obesity development in a different manner, which necessitates sex-specific management. Identifying crucial factors that protect the cardiovascular system is essential to enhance primary and secondary prevention of cardiovascular diseases and should be explicitly studied from the perspective of sex differences. It seems that AMP-dependent protein kinase (AMPK) may be such a factor since it has the protective role of AMPK in the cardiovascular system, has anti-diabetic properties, and is regulated by sex hormones. Those findings highlight the potential cardiometabolic benefits of AMPK, making it an essential factor to consider. Here, we review information about the cross-talk between AMPK and sex hormones as a critical point in cardiometabolic disease development and progression and a target for therapeutic intervention in human disease.

Serum testosterone level correlates with left ventricular hypertrophy in older women

Introduction

Sex hormones may play an important role in age-related cardiac remodeling. However, their impact on cardiac structure and function in females of advanced age still remains unclear. The aim of this study is to evaluate the relationship between sex hormones level and echocardiographic parameters in older women with concomitant cardiovascular diseases.

Materials and Methods

The study group included 52 community-dwelling women with mean age 79.5 ± 2.8 years, consecutive patients of an outpatient geriatric clinic. In all the subjects, a transthoracic echocardiogram was performed and serum testosterone, estradiol, follicle-stimulating hormone, luteinising hormone, dehydroepiandrosterone sulphate, and cortisol levels were determined.

Results

Testosterone level correlated positively with interventricular septum diastolic dimension (IVSd) (rS=0.293, p<0.05), left ventricular mass index (rS=0.285, p<0.05), E/E' ratio (rS=0.301, p<0.05), and negatively with E' (rS=-0.301, p<0.05). Estradiol level showed a positive correlation with the posterior wall dimension (rS=0.28, p<0.05). Besides, no significant correlations between clinical or echocardiographic parameters and other hormones were observed. Female subjects with diagnosed left ventricular hypertrophy (LVH) (n=34) were characterized by a significantly higher rate of hypertension (p=0.011), higher waist-to-height ratio (p=0.009), higher testosterone level (0.82 vs. 0.48 nmol/L, p=0.024), higher testosterone/estradiol ratio (16.4 vs. 9.9, p=0.021), and received more anti-hypertensive drugs (p=0.030). In a multiple stepwise logistic regression, the best determinants of LVH were the presence of hypertension (OR=6.51; 95% CI 1.62-26.1), and testosterone level (OR= 6.6; 95% CI 1.19-36.6).

Conclusions

Higher serum testosterone levels may contribute to pathological cardiac remodeling, especially in hypertensive women. Estradiol, gonadotropins, DHEAS, and cortisol were not related to echocardiographic parameters.

Role of β-blockers in Preventing Heart Failure and Major Adverse Cardiac Events Post Myocardial Infarction

β-blockers have been widely utilized as a part of acute myocardial infarction (AMI) treatment for the past 40 years. Patients receiving β-adrenergic blockers for an extended period following myocardial infarction have a higher chance of surviving. Although many patients benefited from β-blockers, many do not, including those with myocardial infarction, left ventricle dysfunction, chronic pulmonary disease, and elderly people. In individuals with the post-acute coronary syndrome and normal left ventricular ejection fraction (LVEF), the appropriate duration of betablocker therapy is still unknown. There is also no time limit for those without angina and those who do not need β-blockers for arrhythmia or hypertension. Interestingly, β-blockers have been prescribed for more than four decades. The novel mechanism of action on cellular compartments has been found continually, which opens a new way for their potential application in cardiac failure and other cardiac events like post-myocardial infarction. Here, in this review, we studied β-blocker usage in these circumstances and the current recommendations for β-blocker use from clinical practice guidelines.

Cytokine Pathways in Cardiac Dysfunction following Burn Injury and Changes in Genome Expression

In 2016, an estimated 486,000 individuals sustained burn injuries requiring medical attention. Severe burn injuries lead to a persistent, hyperinflammatory response that may last up to 2 years. The persistent release of inflammatory mediators contributes to end-organ dysfunction and changes in genome expression. Burn-induced cardiac dysfunction may lead to heart failure and changes in cardiac remodeling. Cytokines promote the inflammatory cascade and promulgate mechanisms resulting in cardiac dysfunction. Here, we review the mechanisms by which TNFα, IL-1 beta, IL-6, and IL-10 cause cardiac dysfunction in post-burn injuries. We additionally review changes in the cytokine transcriptome caused by inflammation and burn injuries.

Sex/Gender- and Age-Related Differences in β-Adrenergic Receptor Signaling in Cardiovascular Diseases

Sex differences in cardiovascular disease (CVD) are often recognized from experimental and clinical studies examining the prevalence, manifestations, and response to therapies. Compared to age-matched men, women tend to have reduced CV risk and a better prognosis in the premenopausal period. However, with menopause, this risk increases exponentially, surpassing that of men. Although several mechanisms have been provided, including sex hormones, an emerging role in these sex differences has been suggested for β-adrenergic receptor (β-AR) signaling. Importantly, β-ARs are the most important G protein-coupled receptors (GPCRs), expressed in almost all the cell types of the CV system, and involved in physiological and pathophysiological processes. Consistent with their role, for decades, βARs have been considered the first targets for rational drug design to fight CVDs. Of note, β-ARs are seemingly associated with different CV outcomes in females compared with males. In addition, even if there is a critical inverse correlation between β-AR responsiveness and aging, it has been reported that gender is crucially involved in this age-related effect. This review will discuss how β-ARs impact the CV risk and response to anti-CVD therapies, also concerning sex and age. Further, we will explore how estrogens impact β-AR signaling in women.

Sex Differences in Cardiovascular Diseases: A Matter of Estrogens, Ceramides, and Sphingosine 1-Phosphate

The medical community recognizes sex-related differences in pathophysiology and cardiovascular disease outcomes (CVD), culminating with heart failure. In general, pre-menopausal women tend to have a better prognosis than men. Explaining why this occurs is not a simple matter. For decades, sex hormones like estrogens (Es) have been identified as one of the leading factors driving these sex differences. Indeed, Es seem protective in women as their decline, during and after menopause, coincides with an increased CV risk and HF development. However, clinical trials demonstrated that E replacement in post-menopause women results in adverse cardiac events and increased risk of breast cancer. Thus, a deeper understanding of E-related mechanisms is needed to provide a vital gateway toward better CVD prevention and treatment in women. Of note, sphingolipids (SLs) and their metabolism are strictly related to E activities. Among the SLs, ceramide and sphingosine 1-phosphate play essential roles in mammalian physiology, particularly in the CV system, and appear differently modulated in males and females. In keeping with this view, here we explore the most recent experimental and clinical observations about the role of E and SL metabolism, emphasizing how these factors impact the CV system.

Cardiovascular, Metabolic and Inflammatory Changes after Ovariectomy and Estradiol Substitution in Hereditary Hypertriglyceridemic Rats

Background: If menopause is really independent risk factor for cardiovascular disease is still under debate. We studied if ovariectomy in the model of insulin resistance causes cardiovascular changes, to what extent are these changes reversible by estradiol substitution and if they are accompanied by changes in other organs and tissues. Methods: Hereditary hypertriglyceridemic female rats were divided into three groups: ovariectomized at 8th week (n = 6), ovariectomized with 17-β estradiol substitution (n = 6), and the sham group (n = 5). The strain of abdominal aorta measured by ultrasound, expression of vascular genes, weight and content of myocardium and also non-cardiac parameters were analyzed. Results: After ovariectomy, the strain of abdominal aorta, expression of nitric oxide synthase in abdominal aorta, relative weight of myocardium and of the left ventricle and circulating interleukin-6 decreased; these changes were reversed by estradiol substitution. Interestingly, the content of triglycerides in myocardium did not change after ovariectomy, but significantly increased after estradiol substitution while adiposity index did not change after ovariectomy, but significantly decreased after estradiol substitution. Conclusion: Vascular and cardiac parameters under study differed in their response to ovariectomy and estradiol substitution. This indicates different effects of ovariectomy and estradiol on different cardiovascular but also extracardiac structures.

Sex influences the effect of adiposity on arterial stiffness and renin‐angiotensin aldosterone system activity in young adults

Introduction

Methods

Results

Conclusion

Effects of Sex and 17 β-Estradiol on Cardiac Fibroblast Morphology and Signaling Activities In Vitro

Several studies have demonstrated estrogen's cardioprotective abilities in decreasing the fibrotic response of cardiac fibroblasts (CFs). However, the majority of these studies are not sex-specific, and those at the cellular level utilize tissue culture plastic, a substrate with a much higher stiffness than physiological conditions. Understanding the intrinsic differences between male and female CFs under more physiologically "healthy" conditions will help to elucidate the divergences in their complex signaling networks. We aimed to do this by conducting a sex-disaggregated analysis of changes in cellular morphology and relative levels of profibrotic signaling proteins in CFs cultured on 8 kPa stiffness plates with and without 17 β-estradiol (E2). Cyclic immunofluorescent analysis indicated that there was a negligible change in cellular morphology due to sex and E2 treatment and that the differences between male and female CFs occur at a biochemical rather than structural level. Several proteins corresponding to profibrotic activity had various sex-specific responses with and without E2 treatment. Single-cell correlation analysis exhibited varied protein-protein interaction across experimental conditions. These findings demonstrate the need for further research into the dimorphisms of male and female CFs to develop better tailored sex-informed prevention and treatment interventions of cardiac fibrosis.