Hypertrophic remodeling: gender differences in the early response to left ventricular pressure overload

The Canadian Women's Heart Health Alliance ATLAS on the Epidemiology, Diagnosis, and Management of Cardiovascular Disease in Women - Chapter 8: Knowledge Gaps and Status of Existing Research Programs in Canada

Despite significant progress in medical research and public health efforts, gaps in knowledge of women's heart health remain across epidemiology, presentation, management, outcomes, education, research, and publications. Historically, heart disease was viewed primarily as a condition in men and male individuals, leading to limited understanding of the unique risks and symptoms that women experience. These knowledge gaps are particularly problematic because globally heart disease is the leading cause of death for women. Until recently, sex and gender have not been addressed in cardiovascular research, including in preclinical and clinical research. Recruitment was often limited to male participants and individuals identifying as men, and data analysis according to sex or gender was not conducted, leading to a lack of data on how treatments and interventions might affect female patients and individuals who identify as women differently. This lack of data has led to suboptimal treatment and limitations in our understanding of the underlying mechanisms of heart disease in women, and is directly related to limited awareness and knowledge gaps in professional training and public education. Women are often unaware of their risk factors for heart disease or symptoms they might experience, leading to delays in diagnosis and treatments. Additionally, health care providers might not receive adequate training to diagnose and treat heart disease in women, leading to misdiagnosis or undertreatment. Addressing these knowledge gaps requires a multipronged approach, including education and policy change, built on evidence-based research. In this chapter we review the current state of existing cardiovascular research in Canada with a specific focus on women.

Elevated systolic pulmonary artery pressure is a substantial predictor of increased mortality after transcatheter aortic valve replacement in males, not in females

BACKGROUND

While pulmonary hypertension (PH) in patients with severe aortic valve stenosis (AS) is associated with increased mortality after transcatheter aortic valve replacement (TAVR), there is limited data on gender differences in the effects on long-term survival.

OBJECTIVE

The aim of this retrospective, multicenter study was to investigate the prognostic impact of pre-interventional PH on survival of TAVR patients with respect to gender.

METHODS

303 patients undergoing TAVR underwent echocardiography to detect PH prior to TAVR via measurement of systolic pulmonary artery pressure (sPAP). Different cut-off values were set for the presence of PH. The primary endpoint was all-cause mortality at 1, 3 and 5 years.

RESULTS

Kaplan-Meier analysis by gender showed that only males exhibited significant increased mortality at elevated sPAP values during the entire follow-up period of 5 years (sPAP ≥ 40 mmHg: p ≤ 0.001 and sPAP ≥ 50 mmHg: p ≤ 0.001 in 1- to 5-year survival), whereas high sPAP values had no effect on survival in females. In Cox regression analysis based on the selected sPAP thresholds, male gender was an independent risk factor for long-term mortality after TAVR in all time courses.

CONCLUSION

Male gender was an isolated risk factor for premature death after TAVR in patients with echocardiographic evidence of PH and severe AS. This could mean that, the indication for TAVR should be discussed more critically in men with severe AS and an elevated sPAP, while in females, PH should not be an exclusion criterion for TAVR.

Sex Differences in the Progression and Long-Term Outcomes of Native Mild to Moderate Aortic Stenosis

BACKGROUND

There are limited data on the sex differences in the hemodynamic progression and outcomes of early-stage aortic stenosis (AS).

OBJECTIVES

The authors sought to determine sex differences in hemodynamic progression and outcomes of mild to moderate native AS.

METHODS

This was a retrospective observational cohort study including patients with mild to moderate native tricuspid AS from the Cleveland Clinic echocardiographic database between 2008 and 2016 and followed until 2018. All-cause mortality, aortic valve replacement (AVR), and disease progression assessed by annualized changes in echocardiographic parameters were analyzed based on sex.

RESULTS

The authors included 2,549 patients (mean age, 74 ± 7 years and 42.5% women) followed over a median duration of 5.7 years. There was no difference in all-cause mortality between sexes irrespective of age, baseline disease severity, progression to severe AS, and receipt of AVR. Relative to men, women had similar all-cause mortality but lower risk of AVR (adjusted HR: 0.81 [95% CI: 0.67-0.91]; P = 0.009) at 10 years. On 1:1 propensity-matched analysis, men had a significantly faster disease progression represented by greater increases in the median of annualized change in mean gradient (2.10 vs 1.15 mm Hg/y, respectively, P < 0.001), maximum transvalvular velocity (0.42 vs 0.28 m/s/y), left ventricular end-diastolic diameters (0.15 vs 0.048 mm/m2.7/y) (P = 0.014). Women have significantly higher left ventricular ejection fraction, filling pressures, and left ventricular septum thickness over time on follow-up echocardiograms compared with men.

CONCLUSIONS

Women with mild to moderate AS had slower hemodynamic progression of AS, were more likely to have preserved left ventricular ejection fraction and concentric left ventricular hypertrophy in addition to lower incidence of AVR compared with men despite similar mortality. These findings provide further evidence that there are distinct sex-specific longitudinal echocardiographic and clinical profiles in patients with AS.

Sex-specific responses to slow progressive pressure overload in a large animal model of HFpEF

Approximately 50% of all heart failure (HF) diagnoses can be classified as HF with preserved ejection fraction (HFpEF). HFpEF is more prevalent in females compared with males, but the underlying mechanisms are unknown. We previously showed that pressure overload (PO) in male felines induces a cardiopulmonary phenotype with essential features of human HFpEF. The goal of this study was to determine if slow progressive PO induces distinct cardiopulmonary phenotypes in females and males in the absence of other pathological stressors. Female and male felines underwent aortic constriction (banding) or sham surgery after baseline echocardiography, pulmonary function testing, and blood sampling. These assessments were repeated at 2 and 4 mo postsurgery to document the effects of slow progressive pressure overload. At 4 mo, invasive hemodynamic studies were also performed. Left ventricle (LV) tissue was collected for histology, myofibril mechanics, extracellular matrix (ECM) mass spectrometry, and single-nucleus RNA sequencing (snRNAseq). The induced pressure overload (PO) was not different between sexes. PO also induced comparable changes in LV wall thickness and myocyte cross-sectional area in both sexes. Both sexes had preserved ejection fraction, but males had a slightly more robust phenotype in hemodynamic and pulmonary parameters. There was no difference in LV fibrosis and ECM composition between banded male and female animals. LV snRNAseq revealed changes in gene programs of individual cell types unique to males and females after PO. Based on these results, both sexes develop cardiopulmonary dysfunction but the phenotype is somewhat less advanced in females.NEW & NOTEWORTHY We performed a comprehensive assessment to evaluate the effects of slow progressive pressure overload on cardiopulmonary function in a large animal model of heart failure with preserved ejection fraction (HFpEF) in males and females. Functional and structural assessments were performed at the organ, tissue, cellular, protein, and transcriptional levels. This is the first study to compare snRNAseq and ECM mass spectrometry of HFpEF myocardium from males and females. The results broaden our understanding of the pathophysiological response of both sexes to pressure overload. Both sexes developed a robust cardiopulmonary phenotype, but the phenotype was equal or a bit less robust in females.

Percutaneous cutting balloon angioplasty for the treatment of renovascular hypertension in children and adolescents

OBJECTIVE

Percutaneous transluminal renal angioplasty (PTRA), the recommended treatment in children with renovascular hypertension (RVH), often has unsatisfactory outcomes. Cutting balloons may improve the results of angioplasty in different vascular beds with complex and resistant lesions. We retrospectively analysed the effects of percutaneous cutting balloon angioplasty (PCBA) on blood pressure, cardiac mass and renal artery acceleration time in children/adolescents referred to our centre for RVH.

PATIENTS AND METHODS

Thirteen patients (aged 9-19 years) with renal artery stenosis (RAS) and severe hypertension were identified. RASs were focal fibromuscular (FMD) or FMD-like dysplasia (in six cases bilateral, in five associated with mid aortic syndrome). Ten patients had uncontrolled hypertension, in nine cases associated with left ventricular hypertrophy (LVH). Acceleration time was abnormal in all stenotic arteries. Eighteen PCBA were performed, in three arteries associated with stent implantation.

RESULTS

PCBA was technically successful in all individuals without major complications. In one patient, an intra-stent restenosis occurred, successfully redilated with conventional angioplasty without recurrence at 4 years distance. One year after PCBA, mean SBP and DBPs were markedly reduced from 146 ± 25 to 121 ± 10 mmHg and from 87 ± 11 to 65 ± 12 mmHg, respectively (P < 0.001 for both). At that time, hypertension was cured in seven children and controlled in five individuals. This favourable outcome was confirmed with ambulatory blood pressure measurement in four patients. At the latest follow-up, left ventricular mass and acceleration time were normal in all patients.

CONCLUSION

PCBA proved to be a well tolerated and effective procedure that can be considered as an alternative to PTRA to treat hypertensive children/adolescents with recurrent or resistant RAS.

Sex similarities and differences in the reverse and anti-remodeling effect of pressure unloading therapy in a rat model of aortic banding and debanding

BACKGROUND

Investigating the effect of sex on pressure unloading therapy in a clinical scenario is limited by several non-standardized factors. Hence, we sought to study sex-related similarities and differences under laboratory conditions.

METHODS

Pressure overload was induced in male and female rats by aortic banding (AB) for 6 and 12 weeks. Age-matched sham operated animals served as controls. Pressure unloading was performed by aortic debanding at week 6. Different aspects of myocardial remodeling were characterized by echocardiography, pressure-volume analysis, histology, qRT-PCR and explorative proteomics.

RESULTS

Hypertrophy, increased fetal gene expression, interstitial fibrosis, and prolonged active relaxation were noted in the AB groups at week 6 in both sexes. However, decompensation of systolic function and further deterioration of diastolic function only occurred in male AB rats at week 12. AB induced similar proteomic alterations in both sexes at week 6, while characteristic differences were found at week 12. After debanding, regression of hypertrophy and recovery of diastolic function took place to a similar extent in both sexes. Nevertheless, fibrosis, transcription of β-to-α myosin-heavy chain ratio, and myocardial proteomic alterations were reduced to a greater degree in females compared to males. Debanding exposed anti-remodeling properties in both sexes, and prevented the functional decline in males.

CONCLUSIONS

Female sex is associated with greater reversibility of fibrosis, fetal gene expression, and proteomic alterations. Nevertheless, pressure unloading exposes a more pronounced anti-remodeling effect on the functional level in males, which is attributed to the more progressive functional deterioration in AB animals.

Heart failure in diabetes

Heart failure and cardiovascular disorders represent the leading cause of death in diabetic patients. Here we present a systematic review of the main mechanisms underlying the development of diabetic cardiomyopathy. We also provide an excursus on the relative contribution of cardiomyocytes, fibroblasts, endothelial and smooth muscle cells to the pathophysiology of heart failure in diabetes. After having described the preclinical tools currently available to dissect the mechanisms of this complex disease, we conclude with a section on the most recent updates of the literature on clinical management.

Incidence and Outcomes of Acute Heart Failure With Preserved Versus Reduced Ejection Fraction in SPRINT

BACKGROUND

In the SPRINT (Systolic Blood Pressure Intervention Trial), intensive BP treatment reduced acute decompensated heart failure (ADHF) events. Here, we report the effect on HF with preserved ejection fraction (HFpEF) and HF with reduced EF (HFrEF) and their subsequent outcomes.

METHODS

Incident ADHF was defined as hospitalization or emergency department visit, confirmed, and formally adjudicated by a blinded events committee using standardized protocols. HFpEF was defined as EF ≥45%, and HFrEF was EF <45%.

RESULTS

Among the 133 participants with incident ADHF who had EF assessment, 69 (52%) had HFpEF and 64 (48%) had HFrEF (P value: 0.73). During average 3.3 years follow-up in those who developed incident ADHF, rates of subsequent all-cause and HF hospital readmission and mortality were high, but there were no significant differences between those who developed HFpEF versus HFrEF. Randomization to the intensive arm had no effect on subsequent mortality or readmissions after the initial ADHF event, irrespective of EF subtype. During follow-up among participants who developed HFpEF, although relatively modest number of events limited statistical power, age was an independent predictor of all-cause mortality, and Black race independently predicted all-cause and HF hospital readmission.

CONCLUSIONS

In SPRINT, intensive BP reduction decreased both acute decompensated HFpEF and HFrEF events. After initial incident ADHF, rates of subsequent hospital admission and mortality were high and were similar for those who developed HFpEF or HFrEF. Randomization to the intensive arm did not alter the risks for subsequent all-cause, or HF events in either HFpEF or HFrEF. Among those who developed HFpEF, age and Black race were independent predictors of clinical outcomes. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01206062.

Gender Differences after Transcatheter Aortic Valve Replacement (TAVR): Insights from the Italian Clinical Service Project

Background: TAVR is a safe alternative to surgical aortic valve replacement (SAVR); however, sex-related differences are still debated. This research aimed to examine gender differences in a real-world transcatheter aortic valve replacement (TAVR) cohort. Methods: All-comer aortic stenosis (AS) patients undergoing TAVR with a Medtronic valve across 19 Italian sites were prospectively included in the Italian Clinical Service Project (NCT01007474) between 2007 and 2019. The primary endpoint was 1-year mortality. We also investigated 3-year mortality, and ischemic and hemorrhagic endpoints, and we performed a propensity score matching to assemble patients with similar baseline characteristics. Results: Out of 3821 patients, 2149 (56.2%) women were enrolled. Compared with men, women were older (83 ± 6 vs. 81 ± 6 years, p < 0.001), more likely to present severe renal impairment (GFR ≤ 30 mL/min, 26.3% vs. 16.3%, p < 0.001) but had less previous cardiovascular events (all p < 0.001), with a higher mean Society of Thoracic Surgeons (STS) score (7.8% ± 7.1% vs. 7.2 ± 7.5, p < 0.001) and a greater mean aortic gradient (52.4 ± 15.3 vs. 47.3 ± 12.8 mmHg, p < 0.001). Transfemoral TAVR was performed more frequently in women (87.2% vs. 82.1%, p < 0.001), with a higher rate of major vascular complications and life-threatening bleeding (3.9% vs. 2.4%, p = 0.012 and 2.5% vs. 1.4%, p = 0.024). One-year mortality differed between female and male (11.5% vs. 15.0%, p = 0.002), and this difference persisted after adjustment for significant confounding variables (Adj.HR1yr 1.47, 95%IC 1.18–1.82, p < 0.001). Three-year mortality was also significantly lower in women compared with men (19.8% vs. 24.9%, p < 0.001) even after adjustment for age, STS score, eGFR, diabetes and severe COPD (Adj.HR3yr 1.42, 95%IC 1.21–1.68, p < 0.001). These results were confirmed in 689 pairs after propensity score matching. Conclusion: Despite higher rates of peri-procedural complications, women presented better survival than men. This better adaptive response to TAVR may be driven by sex-specific factors.

Heart failure with preserved ejection fraction in humans and mice: embracing clinical complexity in mouse models

Heart failure (HF) with preserved ejection fraction (HFpEF) is a multifactorial disease accounting for a large and increasing proportion of all clinical HF presentations. As a clinical syndrome, HFpEF is characterized by typical signs and symptoms of HF, a distinct cardiac phenotype and raised natriuretic peptides. Non-cardiac comorbidities frequently co-exist and contribute to the pathophysiology of HFpEF. To date, no therapy has proven to improve outcomes in HFpEF, with drug development hampered, at least partly, by lack of consensus on appropriate standards for pre-clinical HFpEF models. Recently, two clinical algorithms (HFA-PEFF and H₂FPEF scores) have been developed to improve and standardize the diagnosis of HFpEF. In this review, we evaluate the translational utility of HFpEF mouse models in the context of these HFpEF scores. We systematically recorded evidence of symptoms and signs of HF or clinical HFpEF features and included several cardiac and extra-cardiac parameters as well as age and sex for each HFpEF mouse model. We found that most of the pre-clinical HFpEF models do not meet the HFpEF clinical criteria, although some multifactorial models resemble human HFpEF to a reasonable extent. We therefore conclude that to optimize the translational value of mouse models to human HFpEF, a novel approach for the development of pre-clinical HFpEF models is needed, taking into account the complex HFpEF pathophysiology in humans.

Effect of Gonadectomy and Angiotensin II Receptor Blockade in a Mouse Model of Isoproterenol-induced Cardiac Diastolic Dysfunction

BACKGROUND

Although heart failure (HF) with preserved ejection fraction (HFpEF) is more common in postmenopausal women than in men, the effect of sex hormones on cardiac diastolic function remains unclear. We examined the effect of gonadectomy with or without the angiotensin receptor blocker olmesartan (Olm) in an isoproterenol (ISO) -induced mouse model of left ventricular hypertrophy (LVH) and cardiac diastolic dysfunction.

METHODS

ISO or ISO with Olm were administered for 28 days in sham-operated male and female, castrated (CAS), and ovariectomized (OVX) mice. LV ejection fraction (EF) and E/A ratio were analyzed by echocardiography, and the LV and lung weight corrected by tibial length were used as indices of LVH and lung congestion, respectively.

RESULTS

On echocardiography, systolic function did not differ between the four groups. LV/tibial length (TL) and Lung/TL significantly increased in all groups. The LV/TL ratio was lower in castrated-ISO vs. Male-Sham-ISO but did not differ between Female-Sham-ISO and OVX-ISO. However, the Lung/TL ratio of OVX-ISO was greater than that of Female-Sham-ISO. Olm prevented LV hypertrophy in all groups. The decrease in E/A and increase in lung weight were improved by Olm in Male-Sham and OVX-ISO but not in the other groups.

CONCLUSION

These sex differences suggest that sex hormones play a pivotal role in modulating cardiac hypertrophy and diastolic dysfunction induced by chronic β-adrenoceptor stimulation, and thus affect the therapeutic potential of angiotensin receptor blockade.

Congestive heart failure model representing aortic banding induced hypertrophy: A study to analyse extent of pressure overload and alteration in myocardial structure and function

Congestive Heart failure (CHF) is a severe pathology representing a major public health problem in industrialized nations which is increasing in prevalence and incidence. The aortic banding rat model provides steady progression of cardiac dysfunction under chronic pressure overload. Present study evaluated two abdominal aortic constriction techniques including constriction of aorta above renal arteries and between renal arteries. The extent of constriction was varied with 22 G and 24 G needles and the duration for evaluation of CHF was also varied by terminating the banded animals after 6 and 8 weeks of banding. Various hemodynamic, ECG and tissue parameters were evaluated after banding to see the progression of CHF. The findings revealed that the constriction of the aorta above both renal arteries with 24 G needle is a better technique amongst other tested banding techniques as the rate of progression of CHF was found to be maximum with it. On the basis of above study, it was concluded that, aortic banding above both renal arteries with 24 G needle is a better technique for induction of pressure overload and for further observation in transition of the cardiac compensatory to decompensatory phase, the duration of the model needs to be prolonged.

Sex Influence on Heart Failure Prognosis

Heart failure (HF) affects 1-2% of the population in developed countries and ~50% of patients living with it are women. Compared to men, women are more likely to be older and suffer hypertension, valvular heart disease, and non-ischemic cardiomyopathy. Since the number of women included in prospective HF studies has been low, much information regarding HF in women has been inferred from clinical trials observations in men and data obtained from registries. Several relevant sex-related differences in HF patients have been described, including biological mechanisms, age, etiology, precipitating factors, comorbidities, left ventricular ejection fraction, treatment effects, and prognosis. Women have greater clinical severity of HF, with more symptoms and worse functional class. However, females with HF have better prognosis compared to males. This survival advantage is particularly impressive given that women are less likely to receive guideline-proven therapies for HF than men. The reasons for this better prognosis are unknown but prior pregnancies may play a role. In this review article we aim to describe sex-related differences in HF and how these differences might explain why women with HF can expect to survive longer than men.

Mitochondrial Reversible Changes Determine Diastolic Function Adaptations During Myocardial (Reverse) Remodeling

BACKGROUND

Often, pressure overload-induced myocardial remodeling does not undergo complete reverse remodeling after decreasing afterload. Recently, mitochondrial abnormalities and oxidative stress have been successively implicated in the pathogenesis of several chronic pressure overload cardiac diseases. Therefore, we aim to clarify the myocardial energetic dysregulation in (reverse) remodeling, mainly focusing on the mitochondria.

METHODS

Thirty-five Wistar Han male rats randomly underwent sham or ascending (supravalvular) aortic banding procedure. Echocardiography revealed that banding induced concentric hypertrophy and diastolic dysfunction (early diastolic transmitral flow velocity to peak early-diastolic annular velocity ratio, E/E': sham, 13.6±2.1, banding, 18.5±4.1, P=0.014) accompanied by increased oxidative stress (dihydroethidium fluorescence: sham, 1.6×10⁸±6.1×10⁷, banding, 2.6×10⁸±4.5×10⁷, P<0.001) and augmented mitochondrial function. After 8 to 9 weeks, half of the banding animals underwent overload relief by an aortic debanding surgery (n=10).

RESULTS

Two weeks later, hypertrophy decreased with the decline of oxidative stress (dihydroethidium fluorescence: banding, 2.6×10⁸±4.5×10⁷, debanding, 1.96×10⁸±6.8×10⁷, P<0.001) and diastolic dysfunction improved simultaneously (E/E': banding, 18.5±4.1, debanding, 15.1±1.8, P=0.029). The reduction of energetic demands imposed by overload relief allowed the mitochondria to reduce its activity and myocardial levels of phosphocreatine, phosphocreatine/ATP, and ATP/ADP to normalize in debanding towards sham values (phosphocreatine: sham, 38.4±7.4, debanding, 35.6±8.7, P=0.71; phosphocreatine/ATP: sham, 1.22±0.23 debanding, 1.11±0.24, P=0.59; ATP/ADP: sham, 6.2±0.9, debanding, 5.6±1.6, P=0.66). Despite the decreased mitochondrial area, complex III and V expression increased in debanding compared with sham or banding. Autophagy and mitophagy-related markers increased in banding and remained higher in debanding rats.

CONCLUSIONS

During compensatory and maladaptive hypertrophy, mitochondria become more active. However, as the disease progresses, the myocardial energetic demands increase and the myocardium becomes energy deficient. During reverse remodeling, the concomitant attenuation of cardiac hypertrophy and oxidative stress allowed myocardial energetics, left ventricle hypertrophy, and diastolic dysfunction to recover. Autophagy and mitophagy are probably involved in the myocardial adaptation to overload and to unload. We conclude that these mitochondrial reversible changes underlie diastolic function adaptations during myocardial (reverse) remodeling.

Cardiac Gated Computed Tomography Angiography Discloses a Correlation Between the Volumes of All Four Cardiac Chambers and Heart Rate in Men But Not in Women

Background: Currently, normal values of the cardiac chambers' volumes are adjusted only for gender and body surface area (BSA). We aim to investigate the association between the heart rate and the volume of each of the four cardiac chambers using cardiac-gated computed tomography angiography (CCTA).

Methods: A total of 350 consecutive patients without known cardiac diseases or significant (>50%) stenosis undergoing CCTA between January 2009 and June 2014 for suspected coronary artery disease were included. Cardiac chamber volumes adjusted to BSA were calculated using automated model-based segmentation analysis software of the CCTA data and correlated with patients' mean heart rate during the scan.

Results: There were 240 men and 110 women, median interquartile range age was 55 years (47–61). Women were older 59.0 years (53.7–64) versus 52.0 years (45.0–59.0), had higher prevalence of hyperlipidemia, diabetes mellitus, anemia, and hypothyroidism, and higher median heart rates 64.0 (59.7–66.0) versus 60.0 (55.0–65.0) (p < 0.001). Men had a negative correlation between the volume of each cardiac chamber and the heart rate [r_{age_adj} = (−0.4)–(−0.27), p < 0.001 for all], whereas such a correlation was not found in women. The multivariate analysis showed that a decrease of five beats per minute was associated with an increase of 4%–5% in volume of each chamber in men. There was no such association among females.

Conclusions: Lower heart rate is associated with an increase of each cardiac chamber volume by CCTA in men. This association is not found in women. More extensive studies are required to further elaborate on these gender differences.

Sex related differences in the pathogenesis of organ fibrosis

The development of organ fibrosis has garnered rising attention as multiple diseases of increasing and/or high prevalence appear to progress to the chronic stage. Such is the case for heart, kidney, liver, and lung where diseases such as diabetes, idiopathic/autoimmune disorders, and nonalcoholic liver disease appear to notably drive the development of fibrosis. Noteworthy is that the severity of these pathologies is characteristically compounded by aging. For these reasons, research groups and drug companies have identified fibrosis as a therapeutic target for which currently, there are essentially no effective options. Although a limited body of published studies are available, most literature indicates that in multiple organs, premenopausal women are protected from developing severe forms of fibrosis suggesting an important role for sex hormones in mitigating this process. Investigators have implemented relevant animal models of organ disease linked to fibrosis supporting in general, these observations. In vitro studies and transgenic animals models have also been used in an attempt to understand the role that sex hormones and related receptors play in the development of fibrosis. However, in the setting of chronic disease in some organs such as the heart older (postmenopausal) women within a few years can quickly approach men in disease severity and develop significant degrees of fibrosis. This review summarizes the current body of relevant literature and highlights the imperative need for a major focus to be placed on understanding the manner in which sex and the presence or absence of related hormones modulates cell phenotypes so as to allow for fibrosis to develop.

Incomplete structural reverse remodeling from late-stage left ventricular hypertrophy impedes the recovery of diastolic but not systolic dysfunction in rats

OBJECTIVE

Pressure overload-induced left ventricular myocardial hypertrophy (LVH) regresses after pressure unloading. However, distinct structural alterations become less reversible during the progression of LVH, which might influence the restoration of cardiac function. Here, we investigated how a reverse remodeling process from early versus late-stage LVH affects different aspects of left ventricular function.

METHODS

Pressure overload was induced in rats for 6, 12 and 18 weeks. Sham-operated animals were used as controls. Pressure unloading was evoked by removing the aortic constriction at week 6 (early-debanded) and week 12 (late-debanded). Echocardiography and histological analyses were carried out to detect structural alterations. Pressure-volume analysis was performed to assess left ventricular function. Molecular alterations were analyzed by quantitative real-time-PCR, and western blot.

RESULTS

Myocardial hypertrophy regressed to a similar degree in early and late-debanded groups. Accordingly, no differences were detected in the extent of regression regarding left ventricular mass, cardiomyocyte diameter, heart weight-to-tibial length ratio and beta-to-alpha myosin heavy chain expression. In contrast, resorption of interstitial and perivascular myocardial fibrosis was only detected in the early-debanded group, whereas it persisted in the late-debanded group. Removing the aortic constriction normalized ventriculo-arterial coupling and increased systolic performance in both debanded groups. However, the residual dysfunction in active relaxation and passive stiffness was more severe in the late-debanded compared to the early-debanded group.

CONCLUSION

Early debanding led to complete structural reverse remodeling (reduced hypertrophy and fibrosis) and full restoration of left ventricular function. In contrast, myocardial fibrosis persisted after late debanding, which impeded the normalization of diastolic but not systolic function.

Diagnostic Capability and Influence Factors for a New Electrocardiogram Criterion in the Diagnosis of Left Ventricular Hypertrophy in a Chinese Population

INTRODUCTION

Based on a small sample of patients with hypertension, a few studies have reported that the newly proposed SD + SV4 criterion for left ventricular hypertrophy (LVH) is better than traditional criteria. This study aimed to verify the diagnostic capability of the SD + SV4 criterion in a Chinese population with or without hypertension and to analyze the factors affecting the diagnostic accuracy of LVH.

METHODS

A total of 248 patients with LVH or paroxysmal supraventricular tachycardia (PSVT) discharged from Fuwai Hospital from January 2010 to July 2018 were enrolled. Patients with LVH were diagnosed according to the left ventricular mass index calculated by the echocardiogram parameter as the gold standard in this study. The receiver operating curve (ROC) curve was performed to assess the diagnostic capability and cut-off values of the SD + SV4, RavL + SV3, and SV1 + RV5/RV6 criteria for LVH. Then, multivariate logistic regression analyses were performed to in-vestigate the factors affecting the accuracy of the SD + SV4 criterion.

RESULTS

There were 170 (68.5%) patients with hypertension and 110 (44.4%) with PSVT. According to echocardiography, 107 (43.1%) patients were diagnosed with LVH. The area under the curve (AUC) of the SD + SV4 criterion was the largest compared with that of the RavL + SV3 and SV1 + RV5/RV6 criteria (AUC 0.765 vs. 0.718 vs. 0.713, respectively). The sex-specific SD + SV4 criterion had the highest consistency with the gold standard (r = 0.532 ± 0.054, p < 0.01), accompanied by the highest sensitivity (70.1%) and specificity (85.8%). The cut-off values of the sex-specific SD + SV4 criterion for LVH were ≥2.65 mV (male)/2.15 mV (female). The left ventricular ejection fraction (LVEF; OR 0.920, 95% CI 0.882-0.959, p < 0.001) was significantly different between the SD + SV4 criterion and the gold standard for LVH after adjusting for hypertension, PSVT history, body surface area, interventricular septum thickness, posterior wall thickness, and left ventricular internal diameter.

CONCLUSION

The newly proposed SD + SV4 criterion provides improved sensitivity and accuracy for the diagnosis of LVH in the Chinese population. A decrease in LVEF is an independent factor affecting the diagnostic accuracy of LVH.

Rats are protected from the stress of chronic pressure overload compared with mice

The goal of this investigation was to compare the effects of chronic (4 wk) transverse aortic constriction (TAC) in Sprague-Dawley rats and C57BL/6J mice. TAC, after 1 day, induced similar left ventricular (LV) pressure gradients in both rats (n = 7) and mice (n = 7) (113 ± 5.4 vs. 103 ± 11.5 mmHg), and after 4 wk, the percent increase in LV hypertrophy, as reflected by LV/tibial length (51% vs 49%), was similar in rats (n = 12) and mice (n = 12). After 4 wk of TAC, LV systolic and diastolic function were preserved in TAC rats. In contrast, in TAC mice, LV ejection fraction decreased by 31% compared with sham, along with increases in LV end-diastolic pressure (153%) and LV systolic wall stress (86%). Angiogenesis, as reflected by Ki67 staining of capillaries, increased more in rats (n = 6) than in mice (n = 6; 10 ± 2 vs. 6 ± 1 Ki67-positive cells/field). Myocardial blood flow fell by 55% and coronary reserve by 28% in mice with TAC (n = 4), but they were preserved in rats (n = 4). Myogenesis, as reflected by c-kit-positive myocytes staining positively for troponin I, is another mechanism that can confer protection after TAC. However, the c-kit-positive cells in rats with TAC were all negative for troponin I, indicating the absence of myogenesis. Thus, rats showed relative tolerance to severe pressure overload compared with mice, with mechanisms involving angiogenesis but not myogenesis.

Sex-Related Differences in the Extent of Myocardial Fibrosis in Patients With Aortic Valve Stenosis

OBJECTIVES

The aim of this study was to assess the effect of sex on myocardial fibrosis as assessed by using cardiac magnetic resonance (CMR) imaging in aortic stenosis (AS).

BACKGROUND

Previous studies reported sex-related differences in the left ventricular (LV) remodeling response to pressure overload in AS. However, there are very few data regarding the effect of sex on myocardial fibrosis, a key marker of LV decompensation and adverse cardiac events in AS.

METHODS

A total of 249 patients (mean age 66 ± 13 years; 30% women) with at least mild AS were recruited from 2 prospective observational cohort studies and underwent comprehensive Doppler echocardiography and CMR examinations. On CMR, T1 mapping was used to quantify extracellular volume (ECV) fraction as a marker of diffuse fibrosis, and late gadolinium enhancement (LGE) was used to assess focal fibrosis.

RESULTS

There was no difference in age between women and men (age 66 ± 15 years vs 66 ± 12 years; p = 0.78). However, women presented with a better cardiovascular risk profile than men with less hypertension, dyslipidemia, diabetes, and coronary artery disease (all, p ≤ 0.10). As expected, LV mass index measured by CMR imaging was smaller in women than in men (p < 0.0001). Despite fewer comorbidities, women presented with larger ECV fraction (median: 29.0% [25th to 75th percentiles: 27.4% to 30.6%] vs. 26.8% [25th to 75th percentiles: 25.1% to 28.7%]; p < 0.0001) and similar LGE (median: 4.5% [25th-75th percentiles: 2.3% to 7.0%] vs. 2.8% [25th-75th percentiles: 0.6% to 6.8%]; p = 0.20) than men. In multivariable analysis, female sex remained an independent determinant of higher ECV fraction and LGE (all, p ≤ 0.05).

CONCLUSIONS

Women have greater diffuse and focal myocardial fibrosis independent of the degree of AS severity. These findings further emphasize the sex-related differences in LV remodeling response to pressure overload.

Cardiac hypertrophy with obesity is augmented after pregnancy in C57BL/6 mice

BACKGROUND

Over a third of reproductive-age women in the USA are obese, and the prevalence of cardiovascular disease (CVD) is rising in premenopausal women. Cardiac hypertrophy is an independent predictor of CVD. In contrast to pregnancy, where transiently increased left ventricular (LV) mass is not associated with cardiac damage, obesity-mediated cardiac hypertrophy is pathological. There is a paucity of data describing the effect of obesity during pregnancy on maternal cardiovascular health. The purpose of this study was to determine the long-term effect of obesity during pregnancy on cardiac function and structure in mice.

METHODS

Female C57BL/6 J mice were fed a high-fat (HF) or a low-fat (LF) diet for 20 weeks. After 4 weeks, LF- and HF-fed female mice were either crossed with males to become pregnant or remained non-pregnant controls. Following delivery, pups were euthanized, and females maintained on respective diets. After 20 weeks of diet feeding, cardiac function was quantified by echocardiography, and plasma leptin and adiponectin concentrations quantified in LF- and HF-fed postpartum and nulliparous females. mRNA abundance of genes regulating cardiac hypertrophy and remodeling was quantified from left ventricles using the NanoString nCounter Analysis System. Cardiac fibrosis was assessed from picrosirius red staining of left ventricles.

RESULTS

HF-fed postpartum mice had markedly greater weight gain and fat mass expansion with obesity, associated with significantly increased LV mass, cardiac output, and stroke volume compared with HF-fed nulliparous mice. Plasma leptin, but not adiponectin, concentrations were correlated with LV mass in HF-fed females. HF feeding increased LV posterior wall thickness; however, LV chamber diameter was only increased in HF-fed postpartum females. Despite the marked increase in LV mass in HF-fed postpartum mice, mRNA abundance of genes regulating fibrosis and interstitial collagen content was similar between HF-fed nulliparous and postpartum mice. In contrast, only HF-fed postpartum mice exhibited altered expression of genes regulating the extracellular matrix.

CONCLUSIONS

These results suggest that the combined effects of pregnancy and obesity augment cardiac hypertrophy and promote remodeling. The rising prevalence of CVD in premenopausal women may be attributed to an increased prevalence of women entering pregnancy with an overweight or obese BMI.

Comparison of different methods for the estimation of aortic pulse wave velocity from 4D flow cardiovascular magnetic resonance

BACKGROUND

Arterial pulse wave velocity (PWV) is associated with increased mortality in aging and disease. Several studies have shown the accuracy of applanation tonometry carotid-femoral PWV (Cf-PWV) and the relevance of evaluating central aorta stiffness using 2D cardiovascular magnetic resonance (CMR) to estimate PWV, and aortic distensibility-derived PWV through the theoretical Bramwell-Hill model (BH-PWV). Our aim was to compare various methods of aortic PWV (aoPWV) estimation from 4D flow CMR, in terms of associations with age, Cf-PWV, BH-PWV and left ventricular (LV) mass-to-volume ratio while evaluating inter-observer reproducibility and robustness to temporal resolution.

METHODS

We studied 47 healthy subjects (49.5 ± 18 years) who underwent Cf-PWV and CMR including aortic 4D flow CMR as well as 2D cine SSFP for BH-PWV and LV mass-to-volume ratio estimation. The aorta was semi-automatically segmented from 4D flow data, and mean velocity waveforms were estimated in 25 planes perpendicular to the aortic centerline. 4D flow CMR aoPWV was calculated: using velocity curves at two locations, namely ascending aorta (AAo) and distal descending aorta (DAo) aorta (S1, 2D-like strategy), or using all velocity curves along the entire aortic centreline (3D-like strategies) with iterative transit time (TT) estimates (S2) or a plane fitting of velocity curves systolic upslope (S3). For S1 and S2, TT was calculated using three approaches: cross-correlation (TTc), wavelets (TTw) and Fourier transforms (TTf). Intra-class correlation coefficients (ICC) and Bland-Altman biases (BA) were used to evaluate inter-observer reproducibility and effect of lower temporal resolution.

RESULTS

4D flow CMR aoPWV estimates were significantly (p < 0.05) correlated to the CMR-independent Cf-PWV, BH-PWV, age and LV mass-to-volume ratio, with the strongest correlations for the 3D-like strategy using wavelets TT (S2-TTw) (R = 0.62, 0.65, 0.77 and 0.52, respectively, all p < 0.001). S2-TTw was also highly reproducible (ICC = 0.99, BA = 0.09 m/s) and robust to lower temporal resolution (ICC = 0.97, BA = 0.15 m/s).

CONCLUSIONS

Reproducible 4D flow CMR aoPWV estimates can be obtained using full 3D aortic coverage. Such 4D flow CMR stiffness measures were significantly associated with Cf-PWV, BH-PWV, age and LV mass-to-volume ratio, with a slight superiority of the 3D strategy using wavelets transit time (S2-TTw).

Estradiol Treatment Initiated Early After Ovariectomy Regulates Myocardial Gene Expression and Inhibits Diastolic Dysfunction in Female Cynomolgus Monkeys: Potential Roles for Calcium Homeostasis and Extracellular Matrix Remodeling

Background

Left ventricular (LV) diastolic dysfunction often precedes heart failure with preserved ejection fraction, the dominant form of heart failure in postmenopausal women. The objective of this study was to determine the effect of oral estradiol treatment initiated early after ovariectomy on LV function and myocardial gene expression in female cynomolgus macaques.

Methods and Results

Monkeys were ovariectomized and randomized to receive placebo (control) or oral estradiol at a human‐equivalent dose of 1 mg/day for 8 months. Monkeys then underwent conventional and tissue Doppler imaging to assess cardiac function, followed by transcriptomic and histomorphometric analyses of LV myocardium. Age, body weight, blood pressure, and heart rate were similar between groups. Echocardiographic mitral early and late inflow velocities, mitral annular velocities, and mitral E deceleration slope were higher in estradiol monkeys (all P<0.05), despite similar estimated LV filling pressure. MCP1 (monocyte chemoattractant protein 1) and LV collagen staining were lower in estradiol animals (P<0.05). Microarray analysis revealed differential myocardial expression of 40 genes (>1.2‐fold change; false discovery rate, P<0.05) in estradiol animals relative to controls, which implicated pathways associated with better calcium ion homeostasis and muscle contraction and lower extracellular matrix deposition (P<0.05).

Conclusions

Estradiol treatment initiated soon after ovariectomy resulted in enhanced LV diastolic function, and altered myocardial gene expression towards decreased extracellular matrix deposition, improved myocardial contraction, and calcium homeostasis, suggesting that estradiol directly or indirectly modulates the myocardial transcriptome to preserve cardiovascular function.

Gender disparities in heart failure with mid-range and preserved ejection fraction: Results from APOLLON study

Objective:

This study aimed to examine gender-based differences in epidemiology, clinical characteristics, and management of consecutive patients with heart failure with mid-range ejection fraction (HFmrEF) and heart failure with preserved ejection fraction (HFpEF).

Methods:

The APOLLON trial (A comPrehensive, ObservationaL registry of heart faiLure with mid-range and preserved ejection fractiON) is a multicenter, cross-sectional, and observational study. Consecutive patients with HFmrEF or HFpEF who were admitted to the cardiology clinics were included (NCT03026114). Herein, we performed a post-hoc analysis of data from the APOLLON trial.

Results:

The study population included 1065 (mean age of 67.1±10.6 years, 54% women) patients from 11 sites in Turkey. Compared with men, women were older (68 years vs. 67 years, p<0.001), had higher body mass index (29 kg/m² vs. 27 kg/m², p<0.001), and had higher heart rate (80 bpm vs. 77.5 bpm, p<0.001). Women were more likely to have HFpEF (82% vs. 70.9%, p<0.001), and they differ from men having a higher prevalence of hypertension (78.7% vs. 73.2%, p=0.035) and atrial fibrillation (40.7% vs. 29.9%, p<0.001) but lower prevalence of coronary artery disease (29.5% vs. 54.9%, p<0.001). Women had higher N-terminal pro-B-type natriuretic peptide (691 pg/mL vs. 541 pg/mL, p=0.004), lower hemoglobin (12.7 g/dL vs. 13.8 g/dL, p<0.001), and serum ferritin (51 ng/mL vs. 64 ng/mL, p=0.001) levels, and they had worse diastolic function (E/e’=10 vs. 9, p<0.001). The main cause of heart failure (HF) in women was atrial fibrillation, while it was ischemic heart disease in men.

Conclusion:

Clinical characteristics, laboratory findings, and etiological factors are significantly different in female and male patients with HFmrEF and HFpEF. This study offers a broad perspective for increased awareness about this patient profile in Turkey.

Gender Differences in Cardiac Hypertrophy

Cardiac hypertrophy is an adaptive response to abnormal physiological and pathological stimuli, which can be classified into concentric and eccentric hypertrophy, induced by pressure overload or volume overload, respectively. In both physiological and pathological scenarios, females generally show a more favorable form of hypertrophy compared with their male counterparts. However once established, cardiac hypertrophy is a stronger risk factor for heart failure in females. Pre-menopausal women are better protected against cardiac hypertrophy compared with men, but this protection is abolished following menopause and is partially restored after estrogen replacement therapy. Estrogen exerts its protection by counteracting pro-hypertrophy signaling pathways, whereas androgen mostly plays an opposite role in cardiac hypertrophy. We here summarize the progress in the understanding of sexual dimorphisms in cardiac hypertrophy and highlight recent breakthroughs in the regulatory role of sex hormones and their intricate molecular networks, in order to shed light on gender-oriented therapeutic efficacy for pathological hypertrophy.

The Influence of Sex on Cardiac Physiology and Cardiovascular Diseases

Cardiovascular disease (CVD) is the leading cause of death world-wide. Most of treatment strategies were based on studies conducted on male patients. Studies have shown that significant differences exist between the two sexes in the development of CVD. There are certain differences between men and women in the structure and physiological functions of the heart such as left ventricular mass index, resting heart rate, and contractile function. Accordingly, the pathological features of the heart such as the extend of hypertrophy, fibrosis, and remodeling are also different. In addition, different genders also affect clinical symptoms, responses to treatment and prognosis in the development of CVD. Therefore, it is important to take these differences into consideration when design treatment options for men and women.

Unmasking of oestrogen-dependent changes in left ventricular structure and function in aged female rats: a potential model for pre-heart failure with preserved ejection fraction

KEY POINTS

Heart failure with preserved ejection fraction (HFpEF) is seen more frequently in older women; risk factors include age, hypertension and excess weight. No female animal models of early stage remodelling (pre-HFpEF) have examined the effects that the convergence of such factors have on cardiac structure and function. In this study, we demonstrate that ageing can lead to the development of mild chamber remodelling, diffuse fibrosis and loss of diastolic function. The loss of oestrogens further aggravates such changes by leading to a notable drop in cardiac output (while preserving normal ejection fraction) in the presence of diffuse fibrosis that is more predominant in endocardium and is accompanied by papillary fibrosis. Excess weight did not markedly aggravate such findings. This animal model recapitulates many of the features recognized in older, female HFpEF patients and thus, may serve to examine the effects of candidate therapeutic agents.

ABSTRACT

Two-thirds of patients with heart failure with preserved ejection fraction (HFpEF) are older women, and risk factors include hypertension and excess weight/obesity. Pathophysiological factors that drive early disease development (before heart failure ensues) remain obscure and female animal models are lacking. The study evaluated the intersecting roles of ageing, oestrogen depletion and excess weight on altering cardiac structure/function. Female, 18-month-old, Fischer F344 rats were divided into an aged group, aged + ovariectomy (OVX) and aged + ovariectomy + 10% fructose (OVF) in drinking water (n = 8-16/group) to induce weight gain. Left ventricular (LV) structure/function was monitored by echocardiography. At 22 months of age, animals were anaesthetized and catheter-based haemodynamics evaluated, followed by histological measures of chamber morphometry and collagen density. All aged animals developed hypertension. OVF animals increased body weight. Echocardiography only detected mild chamber remodelling with ageing while intraventricular pressure-volume loop analysis showed significant (P < 0.05) decreases vs. ageing in stroke volume (13% OVX and 15% for OVF), stroke work (34% and 52%) and cardiac output (29% and 27%), and increases in relaxation time (10% OVX) with preserved ejection fraction. Histology indicated papillary and interstitial fibrosis with ageing, which was higher in the endocardium of OVX and OVF groups. With ageing, ovariectomy leads to the loss of diastolic and global LV function while preserving ejection fraction. This model recapitulates many cardiovascular features present in HFpEF patients and may help understand the roles that ageing and oestrogen depletion play in early (pre-HFpEF) disease development.

Sex-specific regulation of cardiac microRNAs targeting mitochondrial proteins in pressure overload

Background

Maladaptive remodeling in pressure overload (PO)-induced left ventricular hypertrophy (LVH) may lead to heart failure. Major sex differences have been reported in this process. The steroid hormone 17β-estradiol, along with its receptors ERα and ERβ, is thought to be crucial for sex differences and is expected to be protective, but this may not hold true for males. Increasing evidence demonstrates a major role for microRNAs (miRNAs) in PO-induced LVH. However, little is known about the effects of biological sex and ERβ on cardiac miRNA regulation and downstream mitochondrial targets. We aimed at the analysis of proteins involved in mitochondrial metabolism testing the hypothesis that they are the target of sex-specific miRNA regulation.

Methods

We employed the transverse aortic constriction model in mice and assessed the levels of five mitochondrial proteins, i.e., Auh, Crat, Decr1, Hadha, and Ndufs4.

Results

We found a significant decrease of the mitochondrial proteins primarily in the male overloaded heart compared with the corresponding control group. Following computational analysis to identify miRNAs putatively targeting these proteins, our in vitro experiments employing miRNA mimics demonstrated the presence of functional target sites for miRNAs in the 3′-untranslated region of the messenger RNAs coding for these proteins. Next, we assessed the levels of the functionally validated miRNAs under PO and found that their expression was induced only in the male overloaded heart. In contrast, there was no significant effect on miRNA expression in male mice with deficient ERβ.

Conclusion

We put forward that the male-specific induction of miRNAs and corresponding downregulation of downstream protein targets involved in mitochondrial metabolism may contribute to sex-specific remodeling in PO-induced LVH.

Impact of gender on outcomes after transcatheter aortic valve implantation

Backgound

The influence of gender on clinical outcomes following transcatheter aortic valve implantation (TAVI) was considerably discrepant in previous studies. We aimed to investigate the impact of gender in our registry.

Methods

The study is a retrospective observational analysis of a prospectively designed cohort (546 consecutive patients treated at the University Hospital Zurich who were enrolled in Swiss TAVI Cohort from May 2008 to April 2014). The Study took place in University Heart Centre at University Hospital Zurich, Switzerland.

Results

Both genders were equally represented with 51.5 % (n = 281) of the populations being females, who were significantly older and had a more pronounced history of hypertension (P < 0.001). Males on the other hand showed a higher incidence of diabetes (P = 0.004), coronary artery disease (P < 0.001), chronic obstructive pulmonary disease (P < 0.001) and renal failure requiring renal replacement therapy (P = 0.018). Patients were followed up for a median of 391 days with a 100% complete follow-up at one year. The primary outcome (all-cause mortality) occurred in 6.8% (n = 37) and 15% (n = 82) of patients at 30 days and one year, respectively. The 30-day all-cause mortality outcome did not significantly differ between females (7.5%) and males (6.0%) (P = 0.619), but one year all-cause mortality occurred significantly more in males than in females (18.7% vs. 11.7%, P < 0.037).

Conclusion

After TAVI implantation for severe aortic stenosis, males have a less favorable long-term (one year) mortality outcome than females.

Impact of left ventricular remodelling patterns on outcomes in patients with aortic stenosis

Aims

The objective of this study was to examine the association between the different patterns of left ventricular (LV) remodelling/hypertrophy on all-cause and cardiovascular mortality in patients with aortic stenosis (AS).

Methods and results

In total, 747 consecutive patients (69 ± 14 years, 57% men) with AS and preserved LV ejection fraction were included in this study. According to LV mass index and relative wall thickness, patients were classified into four LV patterns: normal, concentric remodelling (CR), concentric hypertrophy (CH), and eccentric hypertrophy (EH). One hundred and sixteen patients (15%) had normal pattern, 66 (9%) had EH, 169 (23%) had CR, and 396 (53%) had CH. During a median follow-up of 6.4 years, 339 patients died (242 from cardiovascular causes). CH was associated with higher risk of all-cause mortality compared with the three other LV patterns (all P < 0.05). After multivariable adjustment, CH remained associated with higher risk of mortality (HR = 1.27, 95% CI 1.01-1.61, P = 0.046). There was a significant interaction (P < 0.05) between sex and CH with regards to the impact on mortality: CH was associated with worse outcome in women (P = 0.0001) but not in men (P = 0.22). In multivariable analysis, CH remained associated with higher risk of worse outcome in women (HR = 1.56, 95% CI 1.08-2.24, P = 0.018).

Conclusions

This study shows that CH was independently associated with increased risk of mortality in AS patients with preserved ejection fraction. This association was observed in women but not in men. The pattern of LV remodelling/hypertrophy should be integrated in the risk stratification process in patients with AS.

Pressure-volume analysis reveals characteristic sex-related differences in cardiac function in a rat model of aortic banding-induced myocardial hypertrophy

Sex differences in pressure overload (PO)-induced left ventricular (LV) myocardial hypertrophy (LVH) have been intensely investigated. Nevertheless, sex-related disparities of LV hemodynamics in LVH were not examined in detail. Therefore, we aimed to provide a detailed characterization of distinct aspects of LV function in male and female rats during different stages of LVH. Banding of the abdominal aorta (AB) was performed to induce PO for 6 or 12 wk in male and female rats. Control animals underwent sham operation. The development of LVH was followed by serial echocardiography. Cardiac function was assessed by pressure-volume analysis. Cardiomyocyte hypertrophy and fibrosis were evaluated by histology. At week 6, increased LV mass index, heart weight-to-tibial length, cardiomyocyte diameter, concentric LV geometry, and moderate interstitial fibrosis were detected in both male and female AB rats, indicating the development of an early stage of LVH. Functionally, at this time, impaired active relaxation, increased contractility, and preserved ventricular-arterial coupling were observed in the AB groups in both sexes. In contrast, at week 12, progressive deterioration of LVH-associated structural and functional alterations occurred in male but not female animals with sustained PO. Accordingly, at this later stage, LVH was associated with eccentric remodeling, exacerbated fibrosis, and increased chamber stiffness in male AB rats. Furthermore, augmented contractility declined in male but not female AB animals, resulting in contractility-afterload mismatch. Maintained contractility augmentation, preserved ventricular-arterial coupling, and better myocardial compliance in female rats contribute to sex differences in LV function during the progression of PO-induced LVH. NEW & NOTEWORTHY We investigated sex differences in pressure overload-induced left ventricular myocardial hypertrophy for the first time on the functional level by pressure-volume analysis. We found that left ventricular hypertrophy was initially characterized by prolonged active relaxation, increased contractility, and maintained ventricular-arterial coupling in both sexes. However, at a later stage, augmented contractility declined in mate but not female rats, resulting in contractility-afterload mismatch. Furthermore, in male rats, increased myocardial stiffness also contributed to hypertrophy-associated diastolic dysfunction.

Neonatal cardiomyocyte hypertrophy induced by endothelin-1 is blocked by estradiol acting on GPER

Estradiol (E₂) prevents cardiac hypertrophy, and these protective actions are mediated by estrogen receptor (ER)α and ERβ. The G protein-coupled estrogen receptor (GPER) mediates many estrogenic effects, and its activation in the heart has been observed in ischemia and reperfusion injury or hypertension models; however, the underlying mechanisms need to be fully elucidated. Herein, we investigated whether the protective effect of E₂ against cardiomyocyte hypertrophy induced by endothelin-1 (ET-1) is mediated by GPER and the signaling pathways involved. Isolated neonatal female rat cardiomyocytes were treated with ET-1 (100 nmol/l) for 48 h in the presence or absence of E₂ (10 nmol/l) or GPER agonist G-1 (10 nmol/l) and GPER antagonist G-15 (10 nmol/l). ET-1 increased the surface area of cardiomyocytes, and this was associated with increased expression of atrial and brain natriuretic peptides. Additionally, ET-1 increased the phosphorylation of extracellular signal-related protein kinases-1/2 (ERK1/2). Notably, E₂ or G-1 abolished the hypertrophic actions of ET-1, and that was reversed by G-15. Likewise, E₂ reversed the ET-1-mediated increase of ERK1/2 phosphorylation as well as the decrease of phosphorylated Akt and its upstream activator 3-phosphoinositide-dependent protein kinase-1 (PDK1). These effects were inhibited by G-15, indicating that they are GPER dependent. Confirming the participation of GPER, siRNA silencing of GPER inhibited the antihypertrophic effect of E₂. In conclusion, E₂ plays a key role in antagonizing ET-1-induced hypertrophy in cultured neonatal cardiomyocytes through GPER signaling by a mechanism involving activation of the PDK1 pathway, which would prevent the increase of ERK1/2 activity and consequently the development of hypertrophy.

A Systems Biology Approach to Investigating Sex Differences in Cardiac Hypertrophy

Background

Heart failure preceded by hypertrophy is a leading cause of death, and sex differences in hypertrophy are well known, although the basis for these sex differences is poorly understood.

Methods and Results

This study used a systems biology approach to investigate mechanisms underlying sex differences in cardiac hypertrophy. Male and female mice were treated for 2 and 3 weeks with angiotensin II to induce hypertrophy. Sex differences in cardiac hypertrophy were apparent after 3 weeks of treatment. RNA sequencing was performed on hearts, and sex differences in mRNA expression at baseline and following hypertrophy were observed, as well as within‐sex differences between baseline and hypertrophy. Sex differences in mRNA were substantial at baseline and reduced somewhat with hypertrophy, as the mRNA differences induced by hypertrophy tended to overwhelm the sex differences. We performed an integrative analysis to identify mRNA networks that were differentially regulated in the 2 sexes by hypertrophy and obtained a network centered on PPARα (peroxisome proliferator‐activated receptor α). Mouse experiments further showed that acute inhibition of PPARα blocked sex differences in the development of hypertrophy.

Conclusions

The data in this study suggest that PPARα is involved in the sex‐dimorphic regulation of cardiac hypertrophy.

Preserved heart function after left ventricular pressure overload in adult mice subjected to neonatal cardiac hypoplasia

Intrauterine growth restriction in animal models reduces heart size and cardiomyocyte number at birth. Such incomplete cardiomyocyte endowment is believed to increase susceptibility toward cardiovascular disease in adulthood, a phenomenon referred to as developmental programming. We have previously described a mouse model of impaired myocardial development leading to a 25% reduction of cardiomyocyte number in neonates. This study investigated the response of these hypoplastic hearts to pressure overload in adulthood, applied by abdominal aortic constriction (AAC). Echocardiography revealed a similar hypertrophic response in hypoplastic hearts compared with controls over the first 2 weeks. Subsequently, control mice develop mild left ventricular (LV) dilation, wall thinning and contractile dysfunction 4 weeks after AAC, whereas hypoplastic hearts fully maintain LV dimensions, wall thickness and contractility. At the cellular level, controls exhibit increased cardiomyocyte cross-sectional area after 4 weeks pressure overload compared with sham operated animals, but this hypertrophic response is markedly attenuated in hypoplastic hearts. AAC mediated induction of fibrosis, apoptosis or cell cycle activity was not different between groups. Expression of fetal genes, indicative of pathological conditions, was similar in hypoplastic and control hearts after AAC. Among various signaling pathways involved in cardiac hypertrophy, pressure overload induces p38 MAP-kinase activity in hypoplastic hearts but not controls compared with the respective sham operated animals. In summary, based on the mouse model used in this study, our data indicates that adult hearts after neonatal cardiac hypoplasia show an altered growth response to pressure overload, eventually resulting in better functional outcome compared with controls.

Effect of Intensive Blood Pressure Treatment on Heart Failure Events in the Systolic Blood Pressure Reduction Intervention Trial

BACKGROUND

Acute decompensated heart failure (ADHF) was a frequent common outcome in SPRINT (Systolic Blood Pressure Intervention Trial). We examined whether there was differential reduction in ADHF events from intensive blood pressure [BP] treatment among the 6 key, prespecified subgroups in SPRINT: age ≥75 years, prior cardiovascular disease, chronic kidney disease, women, black race, and 3 levels of baseline systolic BP (≤132 versus >132 to <145 versus ≥145 mm Hg).

METHODS AND RESULTS

ADHF was defined as hospitalization for ADHF, confirmed and formally adjudicated by a blinded events committee using standardized protocols. At 3.29 years follow-up, there were 103 ADHF events (2.2%) among 4683 standard arm participants and 65 ADHF events (1.4%) among 4678 intensive arm participants (Cox proportional hazards ratio, 0.63; 95% confidence interval, 0.46-0.85; P value =0.003). In multivariable analyses, including treatment arm, baseline covariates that were significant predictors for ADHF included chronic kidney disease, cardiovascular disease, age≥75 years, body mass index, and higher systolic BP. The beneficial effect of the intervention on incident ADHF was consistent across all prespecified subgroups. Participants who had incident ADHF had markedly increased risk of subsequent cardiovascular events, including a 27-fold increase (P<0.001) in cardiovascular death.

CONCLUSIONS

Targeting a systolic BP<120 mm Hg, compared with <140 mm Hg, significantly reduced ADHF events, and the benefit was similar across all key, prespecified subgroups. Participants who developed ADHF had markedly increased risk for subsequent cardiovascular events and death, highlighting the importance of strategies aimed at prevention of ADHF, especially intensive BP reduction.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01206062.

Age- and Sex-Related Influences on Left Ventricular Mechanics in Elderly Individuals Free of Prevalent Heart Failure: The ARIC Study (Atherosclerosis Risk in Communities)

BACKGROUND

Advanced age is related to left ventricular (LV) remodeling. We sought to investigate the relationships between aging, elevated hemodynamic load, cardiac mechanics, and LV remodeling in an elderly community-based population.

METHODS AND RESULTS

We studied 1105 subjects (76±5 years, 61% women) without prevalent heart failure, who attended the visit 5 of the ARIC study (Atherosclerosis Risk in Communities). LV global longitudinal strain, global circumferential strain, and torsion indices were analyzed using 3-dimensional echocardiography. Advanced age was associated with greater LV concentricity, lower myocardial diastolic relaxation, reduced global longitudinal strain (adjusted estimate, 0.39±0.19% (SE)/decade; P=0.038), borderline greater global circumferential strain (adjusted estimate, -0.59±0.36% (SE)/decade; P=0.08), and higher torsion indices (adjusted estimate for torsion, 0.33±0.04° (SE)/decade; P<0.001). In addition, greater concentricity was associated with decreased global longitudinal strain and greater torsion in multivariable models (all P<0.001). Women showed smaller LV cavity size, greater concentricity, lower myocardial relaxation velocity E', though demonstrated greater global longitudinal strain, global circumferential strain, and torsion than men (all P<0.05). Overall, subjects with hypertension and increasing age were more likely to have higher torsion, though the association between advanced age and greater torsion was more pronounced in women than in men (both interaction P<0.05).

CONCLUSIONS

In an asymptomatic, senescent community-dwelling population, we observed a distinct, sex-specific pattern of cardiac remodeling. Although we observed worse diastolic and longitudinal function with advanced age or elevated load in both sexes, a significant increase of torsion was more pronounced in women.

Heart Failure with Preserved Ejection Fraction in Older Adults

Most elderly patients, particularly women, who have heart failure, have a preserved ejection fraction. Patients with this syndrome have severe symptoms of exercise intolerance, frequent hospitalizations, and increased mortality. Despite the importance of heart failure with preserved ejection fraction (HFpEF), the understanding of its pathophysiology is incomplete, and optimal treatment remains largely undefined. Unlike the management of HFrEF, there is a paucity of large evidence-based trials demonstrating morbidity and mortality benefit for the treatment of HFpEF. An update is presented on information regarding pathophysiology, diagnosis, management, and future directions in this important and growing disorder.

Pathophysiology of Aortic Valve Stenosis: Is It Both Fibrocalcific and Sex Specific?

Our understanding of the fundamental biology and identification of efficacious therapeutic targets in aortic valve stenosis has lagged far behind the fields of atherosclerosis and heart failure. In this review, we highlight the most clinically relevant problems facing men and women with fibrocalcific aortic valve stenosis, discuss the fundamental biology underlying valve calcification and fibrosis, and identify key molecular points of intersection with sex hormone signaling.

GPER-novel membrane oestrogen receptor

The recent discovery of the G protein-coupled oestrogen receptor (GPER) presents new challenges and opportunities for understanding the physiology, pathophysiology and pharmacology of many diseases. This review will focus on the expression and function of GPER in hypertension, kidney disease, atherosclerosis, vascular remodelling, heart failure, reproduction, metabolic disorders, cancer, environmental health and menopause. Furthermore, this review will highlight the potential of GPER as a therapeutic target.

Female rats with severe left ventricle volume overload exhibit more cardiac hypertrophy but fewer myocardial transcriptional changes than males

Aortic valve regurgitation (AR) imposes a volume overload (VO) to the left ventricle (LV). Male rats with a pathological heart overload usually progress more quickly towards heart failure than females. We examined whether a sexual dimorphism exists in the myocardial transcriptional adaptations to AR. Adult Wistar male and female rats either underwent a sham operation or were induced with AR and then followed for 26 weeks. Female AR rats gained relatively more LV mass than males (75 vs. 42%). They had a similar increase in LV chamber dimensions compared to males but more wall thickening. On the other hand, fatty acid oxidation (FAO)-related LV enzyme activity was only decreased in AR males. The expression of genes encoding FAO-related enzymes was only reduced in AR males and not in females. A similar situation was observed for the expression of genes involved in mitochondrial biogenesis or function as well as for genes encoding for transcription factors implicated in the control of bioenergetics and mitochondrial function (Errα, Errγ or Pgc1α). Although females develop more LV hypertrophy from severe VO, their myocardial gene expression remains closer to normal. This could provide survival benefits for females with severe VO.

Sex Differences in Metabolic Cardiomyopathy

In contrast to ischemic cardiomyopathies which are more common in men, women are over-represented in diabetic cardiomyopathies. Diabetes is a risk factor for cardiovascular disease; however, there is a sexual dimorphism in this risk factor: heart disease is five times more common in diabetic women but only two-times more common in diabetic men. Heart failure with preserved ejection fraction, which is associated with metabolic syndrome, is also more prevalent in women. This review will examine potential mechanisms for the sex differences in metabolic cardiomyopathies. Sex differences in metabolism, calcium handling, nitric oxide, and structural proteins will be evaluated. Nitric oxide synthase and PPARα exhibit sex differences and have also been proposed to mediate the development of hypertrophy and heart failure. We focused on a role for these signalling pathways in regulating sex differences in metabolic cardiomyopathies.

Mechanistic Pathways of Sex Differences in Cardiovascular Disease

Major differences between men and women exist in epidemiology, manifestation, pathophysiology, treatment, and outcome of cardiovascular diseases (CVD), such as coronary artery disease, pressure overload, hypertension, cardiomyopathy, and heart failure. Corresponding sex differences have been studied in a number of animal models, and mechanistic investigations have been undertaken to analyze the observed sex differences. We summarize the biological mechanisms of sex differences in CVD focusing on three main areas, i.e., genetic mechanisms, epigenetic mechanisms, as well as sex hormones and their receptors. We discuss relevant subtypes of sex hormone receptors, as well as genomic and nongenomic, activational and organizational effects of sex hormones. We describe the interaction of sex hormones with intracellular signaling relevant for cardiovascular cells and the cardiovascular system. Sex, sex hormones, and their receptors may affect a number of cellular processes by their synergistic action on multiple targets. We discuss in detail sex differences in organelle function and in biological processes. We conclude that there is a need for a more detailed understanding of sex differences and their underlying mechanisms, which holds the potential to design new drugs that target sex-specific cardiovascular mechanisms and affect phenotypes. The comparison of both sexes may lead to the identification of protective or maladaptive mechanisms in one sex that could serve as a novel therapeutic target in one sex or in both.

Targeted basic research to highlight the role of estrogen and estrogen receptors in the cardiovascular system

Epidemiological, clinical and animal studies revealed that sex differences exist in the manifestation and outcome of cardiovascular disease (CVD). The underlying molecular mechanisms implicated in these sex differences are not fully understood. The reasons for sex differences in CVD are definitely multifactorial, but major evidence points to the contribution of sex steroid hormone, 17β-estradiol (E2), and its receptors, estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ). In this review, we summarize past and present studies that implicate E2 and ER as important determinants of sexual dimorphism in the physiology and pathophysiology of the heart. In particular, we give an overview of studies aimed to reveal the role of E2 and ER in the physiology of the observed sex differences in CVD using ER knock-out mice. Finally, we discuss recent findings from novel transgenic mouse models, which have provided new information on the sexual dimorphic roles of ER specifically in cardiomyocytes under pathological conditions.

The Importance of Biological Sex and Estrogen in Rodent Models of Cardiovascular Health and Disease

Nearly one-third of deaths in the United States are caused by cardiovascular disease (CVD) each year. In the past, CVD was thought to mainly affect men, leading to the exclusion of women and female animals from clinical studies and preclinical research. In light of sexual dimorphisms in CVD, a need exists to examine baseline cardiac differences in humans and the animals used to model CVD. In humans, sex differences are apparent at every level of cardiovascular physiology from action potential duration and mitochondrial energetics to cardiac myocyte and whole-heart contractile function. Biological sex is an important modifier of the development of CVD with younger women generally being protected, but this cardioprotection is lost later in life, suggesting a role for estrogen. Although endogenous estrogen is most likely a mediator of the observed functional differences in both health and disease, the signaling mechanisms involved are complex and are not yet fully understood. To investigate how sex modulates CVD development, animal models are essential tools and should be useful in the development of therapeutics. This review will focus on describing the cardiovascular sexual dimorphisms that exist both physiologically and in common animal models of CVD.

Baseline characteristics of patients with heart failure and preserved ejection fraction at admission with acute heart failure in Saudi Arabia

Heart failure and preserved ejection fraction (HFpEF) is defined as heart failure symptoms and signs with a normal or near-normal ejection fraction (EF) with evidence of diastolic dysfunction. The few Middle Eastern studies that have been conducted were designed to compare patients with heart failure reduced ejection fraction (HFrEF) and HFpEF.The aim of this study was to study Saudi patients with HFpEF who presented with acute heart failure, and define their clinical characteristics and the signs and symptoms of heart failure, echocardiographic findings and medications at admission and at hospital discharge.

Methods

This is a prospective observational study in which patients were included following an acute heart failure presentation with N-terminal pro-BNP (NT-proBNP) > 300 ng/L and left ventricular ejection fraction (LVEF) > 50%. They were admitted to the coronary care unit of king Saud medical city from the period of March 2015 to September 2015.

Results

114 patients were enrolled in the study and assessed at acute admission. Of these, 4% died on day one of admission.The mean ± SD age of 109 included patients was 59 ± 8 years and 55% were women. Hypertension (64%), dyslipidemia (76%), atrial tachyarrhythmia (38%), prior heart failure (33%) and anemia (35%), median NT-proBNP was 2490 ± 125 ng/l at admission. Mean (LVEF) was 61 ± 3, mean LV mass index was 118 ± 11, mean E/e' was 12.2 ± 2, and left atrial volume index was 47 ± 7 mL/m². Mean global left ventricular strain was -13.5 ± 1.5. At discharge the majority of patients were still symptomatic with high NT-proBNP 542 ± 266.

Conclusions

Patients with HFpEF were old with slight female dominance, a high rate of hypertension, diabetes, dyslipidemia and much comorbidity. LVEF was preserved despite depressed left ventricular longitudinal and diastolic functions with high filling pressure. At discharge the patients were still symptomatic calling for further research to reach the best strategy for proper management.

Calcific Aortic Valve Disease: Part 2-Morphomechanical Abnormalities, Gene Reexpression, and Gender Effects on Ventricular Hypertrophy and Its Reversibility

In part 1, we considered cytomolecular mechanisms underlying calcific aortic valve disease (CAVD), hemodynamics, and adaptive feedbacks controlling pathological left ventricular hypertrophy provoked by ensuing aortic valvular stenosis (AVS). In part 2, we survey diverse signal transduction pathways that precede cellular/molecular mechanisms controlling hypertrophic gene expression by activation of specific transcription factors that induce sarcomere replication in-parallel. Such signaling pathways represent potential targets for therapeutic intervention and prevention of decompensation/failure. Hypertrophy provoking signals, in the form of dynamic stresses and ligand/effector molecules that bind to specific receptors to initiate the hypertrophy, are transcribed across the sarcolemma by several second messengers. They comprise intricate feedback mechanisms involving gene network cascades, specific signaling molecules encompassing G protein-coupled receptors and mechanotransducers, and myocardial stresses. Future multidisciplinary studies will characterize the adaptive/maladaptive nature of the AVS-induced hypertrophy, its gender- and individual patient-dependent peculiarities, and its response to surgical/medical interventions. They will herald more effective, precision medicine treatments.