Hypertensive Cardiac Remodeling in Males and Females

Normal Values for Myocardial Work Indices Derived From Pressure-Strain Loop Analyses: From the CCHS

BACKGROUND

Pressure-strain loop analyses is a noninvasive technique capable of evaluating myocardial work. Reference values are needed to benchmark these myocardial work indices for clinical practice.

METHODS

Healthy participants from a general population study were used to establish reference values for global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE) measured by pressure-strain loop analyses. The relation to age and sex was examined. We furthermore examined the proportion of abnormal work indices according to low, intermediate, and high cardiovascular risk by the Framingham risk score.

RESULTS

The healthy sample consisted of 1827 participants (median age, 45 years; 39% men). Lower reference values were GWI, 1576 mm Hg%; GCW, 1708 mm Hg%; and GWE, 93.0% and upper reference value for GWW was 159 mm Hg%. Women exhibited significantly higher GWI, GCW, and GWW and lower GWE. Sex significantly modified the association between all indices and age (P for interaction: 0.001 for GWI, 0.009 for GCW, 0.003 for GWW, and 0.009 for GWE). For men, only GCW increased with age, whereas the other indices did not change with age. For women, GCW increased linearly with increasing age, whereas GWI, GWW, and GWE changed in a curvilinear fashion with age such that GWI increased in younger participants, GWW increased in elderly, and GWE declined concordantly. Abnormalities in myocardial work indices became more frequent with increasing Framingham risk score category (abnormal GWI: 2% versus 4% versus 5%, P=0.001; abnormal GCW: 2% versus 3% versus 4%, P=0.006; abnormal GWW: 3% versus 6% versus 11%, P<0.001; abnormal GWE: 3% versus 4% versus 11%, P<0.001).

CONCLUSIONS

Myocardial work indices differ between sexes and change with age in a sex-dependent manner. Accordingly, we established age- and sex-specific reference values from a general population sample. Abnormal work indices become more frequent with higher clinical risk.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT02993172.

Sex-related differences in clinical presentation and all-cause mortality in patients with cardiac transthyretin amyloidosis and light chain amyloidosis

We aimed to ascertain whether sex-related differences are relevant to clinical presentation, cardiac phenotype and all-cause mortality in different types of cardiac amyloidosis, a field still poorly investigated. Medical files from consecutive patients diagnosed with cardiac amyloidosis between 2000 and 2020, at Careggi University Hospital, were retrospectively evaluated. Over this period, 259 patients (12% females) were diagnosed with wild type transthyretin amyloidosis (wtATTR), 52 (25% females) with hereditary transthyretin amyloidosis (hATTR) and 143 (47% females) with light chain amyloidosis (AL). Women with wtATTR, compared to men, were significantly older at the time of diagnosis and showed higher National Amyloidosis Centre score, thicker normalized interventricular septum, higher diastolic dysfunction and worse right ventricular function. Females with hATTR and AL had lower normalized cardiac mass compared to men, otherwise, bio-humoral parameters, NYHA class, and ECG characteristics were similar. Comparing females and male with wtATTR, hATTR and AL, no differences in Kaplan-Meier curves for all-cause mortality were observed with regard to sex, p-value >0.05. In conclusion, we did not observe major differences in clinical expression related to sex in different types of cardiac amyloidosis: specifically, all-cause mortality was not affected. Nevertheless, women with wtATTR had echocardiographic signs of more advanced disease and higher NAC score at diagnosis suggesting a possible later recognition of disease compared to men.

Increasing fatty acid oxidation elicits a sex-dependent response in failing mouse hearts

BACKGROUND

Reduced fatty acid oxidation (FAO) is a hallmark of metabolic remodeling in heart failure. Enhancing mitochondrial long-chain fatty acid uptake by Acetyl-CoA carboxylase 2 (ACC2) deletion increases FAO and prevents cardiac dysfunction during chronic stresses, but therapeutic efficacy of this approach has not been determined.

METHODS

Male and female ACC2 f/f-MCM (ACC2KO) and their respective littermate controls were subjected to chronic pressure overload by TAC surgery. Tamoxifen injection 3 weeks after TAC induced ACC2 deletion and increased FAO in ACC2KO mice with pathological hypertrophy.

RESULTS

ACC2 deletion in mice with pre-existing cardiac pathology promoted FAO in female and male hearts, but improved cardiac function only in female mice. In males, pressure overload caused a downregulation in the mitochondrial oxidative function. Stimulating FAO by ACC2 deletion caused unproductive acyl-carnitine accumulation, which failed to improve cardiac energetics. In contrast, mitochondrial oxidative capacity was sustained in female pressure overloaded hearts and ACC2 deletion improved myocardial energetics. Mechanistically, we revealed a sex-dependent regulation of PPARα signaling pathway in heart failure, which accounted for the differential response to ACC2 deletion.

CONCLUSION

Metabolic remodeling in the failing heart is sex-dependent which could determine the response to metabolic intervention. The findings suggest that both mitochondrial oxidative capacity and substrate preference should be considered for metabolic therapy of heart failure.

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.

Sex-Specific Associations of Cardiovascular Risk Factors and Biomarkers With Incident Heart Failure

BACKGROUND

Whether cardiovascular (CV) disease risk factors and biomarkers associate differentially with heart failure (HF) risk in men and women is unclear.

OBJECTIVES

The purpose of this study was to evaluate sex-specific associations of CV risk factors and biomarkers with incident HF.

METHODS

The analysis was performed using data from 4 community-based cohorts with 12.5 years of follow-up. Participants (recruited between 1989 and 2002) were free of HF at baseline. Biomarker measurements included natriuretic peptides, cardiac troponins, plasminogen activator inhibitor-1, D-dimer, fibrinogen, C-reactive protein, sST2, galectin-3, cystatin-C, and urinary albumin-to-creatinine ratio.

RESULTS

Among 22,756 participants (mean age 60 ± 13 years, 53% women), HF occurred in 2,095 participants (47% women). Age, smoking, type 2 diabetes mellitus, hypertension, body mass index, atrial fibrillation, myocardial infarction, left ventricular hypertrophy, and left bundle branch block were strongly associated with HF in both sexes (p < 0.001), and the combined clinical model had good discrimination in men (C-statistic = 0.80) and in women (C-statistic = 0.83). The majority of biomarkers were strongly and similarly associated with HF in both sexes. The clinical model improved modestly after adding natriuretic peptides in men (ΔC-statistic = 0.006; likelihood ratio chi-square = 146; p < 0.001), and after adding cardiac troponins in women (ΔC-statistic = 0.003; likelihood ratio chi-square = 73; p < 0.001).

CONCLUSIONS

CV risk factors are strongly and similarly associated with incident HF in both sexes, highlighting the similar importance of risk factor control in reducing HF risk in the community. There are subtle sex-related differences in the predictive value of individual biomarkers, but the overall improvement in HF risk estimation when included in a clinical HF risk prediction model is limited in both sexes.

H3K27ac acetylome signatures reveal the epigenomic reorganization in remodeled non-failing human hearts

BACKGROUND

H3K27ac histone acetylome changes contribute to the phenotypic response in heart diseases, particularly in end-stage heart failure. However, such epigenetic alterations have not been systematically investigated in remodeled non-failing human hearts. Therefore, valuable insight into cardiac dysfunction in early remodeling is lacking. This study aimed to reveal the acetylation changes of chromatin regions in response to myocardial remodeling and their correlations to transcriptional changes of neighboring genes.

RESULTS

We detected chromatin regions with differential acetylation activity (DARs; Padj. < 0.05) between remodeled non-failing patient hearts and healthy donor hearts. The acetylation level of the chromatin region correlated with its RNA polymerase II occupancy level and the mRNA expression level of its adjacent gene per sample. Annotated genes from DARs were enriched in disease-related pathways, including fibrosis and cell metabolism regulation. DARs that change in the same direction have a tendency to cluster together, suggesting the well-reorganized chromatin architecture that facilitates the interactions of regulatory domains in response to myocardial remodeling. We further show the differences between the acetylation level and the mRNA expression level of cell-type-specific markers for cardiomyocytes and 11 non-myocyte cell types. Notably, we identified transcriptome factor (TF) binding motifs that were enriched in DARs and defined TFs that were predicted to bind to these motifs. We further showed 64 genes coding for these TFs that were differentially expressed in remodeled myocardium when compared with controls.

CONCLUSIONS

Our study reveals extensive novel insight on myocardial remodeling at the DNA regulatory level. Differences between the acetylation level and the transcriptional level of cell-type-specific markers suggest additional mechanism(s) between acetylome and transcriptome. By integrating these two layers of epigenetic profiles, we further provide promising TF-encoding genes that could serve as master regulators of myocardial remodeling. Combined, our findings highlight the important role of chromatin regulatory signatures in understanding disease etiology.

Cardioprotective Effects of Dietary Phytochemicals on Oxidative Stress in Heart Failure by a Sex-Gender-Oriented Point of View

Dietary phytochemicals are considered an innovative strategy that helps to reduce cardiovascular risk factors. Some phytochemicals have been shown to play a beneficial role in lipid metabolism, to improve endothelial function and to modify oxidative stress pathways in experimental and clinical models of cardiovascular impairment. Importantly, investigation on phytochemical effect on cardiac remodeling appears to be promising. Nowadays, drug therapy and implantation of devices have demonstrated to ameliorate survival. Of interest, sex-gender seems to influence the response to HF canonical therapies. In fact, starting by the evidence of the feminization of world population and the scarce efficacy and safety of the traditional drugs in women, the search of alternative therapeutic tools has become mandatory. The aim of this review is to summarize the possible role of dietary phytochemicals in HF therapy and the evidence of a different sex-gender-oriented response.

Does gender influence cardiovascular remodeling in C57BL/6J mice fed a high-fat, high-sucrose and high-salt diet?

Animal models are widely used to study the physiopathology of human diseases. However, the influence of gender on modern society diet style-induced cardiovascular disease has not thus far been explored in these models. Thus, this study investigated cardiovascular remodelling in C57BL/6J mice fed a diet rich in saturated fat, sucrose and salt, evaluating gender effect on this process. Male and female C57BL/6J mice were fed AIN93M diet or a modified AIN93M rich in fat, sucrose and salt (HFSS) for 12 weeks. Body mass, water and food intake and cardiovascular remodelling were assessed. The HFSS diet did not lead to body mass gain or glucose metabolism disturbance as assessed by serum glucose, insulin and oral glucose tolerance test. However, female mice on a HFSS diet had increased visceral and subcutaneous adiposity. Only male mice displayed heart hypertrophy. The left ventricle was not hypertrophied in either male or female mice, but its lumen was dilated. Intramyocardial arteries and the thoracic aorta showed media thickening in male mice, but in the female it was only observed in the thoracic aorta. Finally, intramyocardial artery dilation was present in both genders, but not in the aorta. Therefore changes in LV dimensions and arterial remodelling were influenced by both gender and the HFSS diet. In conclusion, male and female C57BL/6J mice suffered cardiovascular remodelling after 12 weeks of HFSS feeding, although they did not develop obesity or diabetes. Sexual dimorphism occurred in response to diet for body adiposity, heart hypertrophy and intramyocardial artery remodelling.

[EPOCHA-D-CHF: gender differences in the prognosis of patients with CHF af-ter acute decompensation (part 2*)]

AIM

To study effects of gender differences in clinical and epidemiological factors on long-term prognosis for patients with acute decompensated heart failure (ADHF).

MATERIALS AND METHODS

A retrospective, observational analysis of a sample of patients (n=718) hospitalized with signs of ADHF with subsequent collecting information about the endpoint (all-cause death) at four years.

RESULTS

Age was a predictor of unfavorable outcome for both men and women (RR, 1.04, 95% CI, 1.02-1.06, p&lt;0.001 and RR, 1.04, 95% CI, 1.03-1.06, p&lt;0.001). Presence of lower extremity edema increased the risk of fatal outcome for men (RR, 2.03, 95% CI, 1.21-3.39, р=0.007) whereas for women, presence of ascites (RR, 3.43, 95% CI, 2.09-5.64, р&lt;0.001) or orthopneic position on admission (RR, 1.51, 95% CI, 1.03-2.23, p=0.04) resulted in the increased risk. For both sexes, the prediction improved with every 10% increase in systolic BP on admission (RR, 0.87, 95% CI, 0.78-0.97, p=0.01 for men and RR, 0.84, 95% CI, 0.76-0.91, p&lt;0.001 for women). Presence of diabetes mellitus affected the prediction only for women (RR, 1.80, 95% CI, 1.34-2.42, p&lt;0.001). A history of myocardial infarction (RR, 1.40, 95% CI, 1.01-1.95, p=0.04 and RR, 1.44, 95% CI, 1.04-1.98, р=0.03), presence of communityacquired pneumonia (RR, 1.90, 95% CI, 1.32-2.74, p&lt;0.001 and RR, 2.38, 95% CI, 1.55-3.68, p&lt;0.001) adversely affected the prediction for men and women, respectively. At the end of study (4 years), the endpoint (all-cause death) was observed in 65.5% of men and 48.1% of women, median survival was 720 и 1168 days, respectively.

CONCLUSIONS

Te long-term prognosis was worse for men hospitalized for ADHF. Presence of congestion signs impaired the prediction for both men and women. Patients with higher systolic BP on admission were characterized with beter survival. A history of diabetes mellitus for women and myocardial infarction or community acquired pneumonia for both sexes worsened the long-term prediction.

Prenatal exposure to testosterone induces cardiac hypertrophy in adult female rats through enhanced Pkcδ expression in cardiac myocytes

High circulating androgen in women with polycystic ovary syndrome (PCOS) may increase the risk of cardiovascular disease in offspring. The aim of the present study is to investigate whether maternal androgen excess in the rat PCOS model would lead to cardiac hypertrophy in offspring. Maternal testosterone propionate (maternal-TP)-treated adult female offspring displayed cardiac hypertrophy associated with local high cardiac dihydrotestosterone (DHT). The molecular markers of cardiac hypertrophy along with androgen receptor (AR) and PKCδ, were increased in the Maternal-TP group. Treatment of primary neonatal rat ventricular cardiomyocytes (NRCMs) and H9c2 cells with DHT significantly increased cell size and upregulated PKCδ expression, which could be attenuated by AR antagonist. Treatment with phorbol 12-myristate 13-acetate (PMA), a PKC activator, significantly increased cell size and upregulated myh7 level. Rottlerin, that may inhibit PKCδ, significantly reduced the hypertrophic effect of DHT and PMA on NRCMs and H9c2 cells. Chromatin immunoprecipitation revealed that AR could bind to Pkcδ promoter. Our results indicate that prenatal exposure to testosterone may induce cardiac hypertrophy in adult female rats through enhanced Pkcδ expression in cardiac myocytes.

Sex, drugs, and heart failure: a sex-sensitive review of the evidence base behind current heart failure clinical guidelines

Heart failure (HF) is a complex disease, almost as common in women as in men. Nonetheless, HF clinical presentation, prognosis, and aetiology vary by sex. This review summarizes the current state of sex-sensitive issues related to HF drugs included in treatment guidelines and suggests future directions for improved care. Heart failure presentation differs between female and male patients: females more often show with hypertensive aetiology and the preserved ejection fraction phenotype, while men more often show ischaemic aetiology and the reduced ejection fraction phenotype. Yet the HF clinical guidelines in Europe, the United States, and Canada do not reflect the sexual dimorphism. Further, in randomized clinical trials of HF medication, women are largely underrepresented, typically consisting of ≥70% men. Given the knowledge that some adverse drug reactions, such as torsade de pointes and angiotensin-converting enzyme inhibitor-induced cough, occur more frequently in women, we emphasize the need to test medications thoroughly in both sexes and explore sexual dimorphisms. To better represent all of the targeted patient population and provide better care for all, two kinds of change must come about: recruitment methods to randomized clinical trial samples need to evolve and the participation needs to seem more attractive to women.

Sex Dimorphism in the Myocardial Response to Aortic Stenosis

OBJECTIVES

The goal of this study was to explore sex differences in myocardial remodeling in aortic stenosis (AS) by using echocardiography, cardiac magnetic resonance (CMR), and biomarkers.

BACKGROUND

AS is a disease of both valve and left ventricle (LV). Sex differences in LV remodeling are reported in AS and may play a role in disease phenotyping.

METHODS

This study was a prospective assessment of patients awaiting surgical valve replacement for severe AS using echocardiography, the 6-min walking test, biomarkers (high-sensitivity troponin T and N-terminal pro-brain natriuretic peptide), and CMR with late gadolinium enhancement and extracellular volume fraction, which dichotomizes the myocardium into matrix and cell volumes. LV remodeling was categorized into normal geometry, concentric remodeling, concentric hypertrophy, and eccentric hypertrophy.

RESULTS

In 168 patients (age 70 ± 10 years, 55% male, indexed aortic valve area 0.40 ± 0.13 cm2/m2, mean gradient 47 ± 4 mm Hg), no sex or age differences in AS severity or functional capacity (6-min walking test) were found. CMR captured sex dimorphism in LV remodeling not apparent by using 2-dimensional echocardiography. Normal geometry (82% female) and concentric remodeling (60% female) dominated in women; concentric hypertrophy (71% male) and eccentric hypertrophy (76% male) dominated in men. Men also had more evidence of LV decompensation (pleural effusions), lower left ventricular ejection fraction (67 ± 16% vs. 74 ± 13%; p < 0.001), and higher levels of N-terminal pro-brain natriuretic peptide (p = 0.04) and high-sensitivity troponin T (p = 0.01). Myocardial fibrosis was higher in men, with higher focal fibrosis (late gadolinium enhancement 16.5 ± 11.2 g vs. 10.5 ± 8.9 g; p < 0.001) and extracellular expansion (matrix volume 28.5 ± 8.8 ml/m2 vs. 21.4 ± 6.3 ml/m2; p < 0.001).

CONCLUSIONS

CMR revealed sex differences in associations between AS and myocardial remodeling not evident from echocardiography. Given equal valve severity, the myocardial response to AS seems more maladaptive in men than previously reported. (Regression of Myocardial Fibrosis After Aortic Valve Replacement [RELIEF-AS]; NCT02174471).

Sirtuin 3 Deficiency Accelerates Hypertensive Cardiac Remodeling by Impairing Angiogenesis

Background

Emerging evidence indicates that impaired angiogenesis may contribute to hypertension‐induced cardiac remodeling. The nicotinamide adenine dinucleotide–dependent deacetylase Sirtuin 3 (SIRT3) has the potential to modulate angiogenesis, but this has not been confirmed. As such, the aim of this study was to examine the relationship between SIRT3‐mediated angiogenesis and cardiac remodeling.

Methods and Results

Our experiments were performed on SIRT3 knockout and age‐matched wild‐type mice infused with angiotensin II (1400 ng/kg per minute) or saline for 14 days. After angiotensin II infusion, SIRT3 knockout mice developed more severe microvascular rarefaction and functional hypoxia in cardiac tissues compared with wild‐type mice. These events were concomitant with mitochondrial dysfunction and enhanced collagen I and collagen III expression, leading to cardiac fibrosis. Silencing SIRT3 facilitated angiotensin II–induced aberrant Pink/Parkin acetylation and impaired mitophagy, while excessive mitochondrial reactive oxygen species generation limited angiogenic capacity in primary mouse cardiac microvascular endothelial cells. Moreover, SIRT3 overexpression in cardiac microvascular endothelial cells enhanced Pink/Parkin‐mediated mitophagy, attenuated mitochondrial reactive oxygen species generation, and restored vessel sprouting and tube formation. In parallel, endothelial cell–specific SIRT3 transgenic mice showed decreased fibrosis, as well as improved cardiac function and microvascular network, compared with wild‐type mice with similar stimuli.

Conclusions

Collectively, these findings suggest that SIRT3 could promote angiogenesis through attenuating mitochondrial dysfunction caused by defective mitophagy.

Amyloid Cardiomyopathy in Hereditary Transthyretin V30M Amyloidosis - Impact of Sex and Amyloid Fibril Composition

Purpose

Transthyretin V30M (ATTR V30M) amyloidosis is a phenotypically diverse disease with symptoms ranging from predominant neuropathy to exclusive cardiac manifestations. The aims of this study were to determine the dispersion of the two types of fibrils found in Swedish ATTR V30M patients -Type A consisting of a mixture of truncated and full length ATTR fibrils and type B fibrils consisting of full length fibrils, and to estimate the severity of cardiac dysfunction in relation to fibril composition and sex.

Material and Methods

Echocardiographic data were analysed in 107 Swedish ATTR V30M patients with their fibril composition determined as either type A or type B. Measurements of left ventricular (LV) dimensions and evaluation of systolic and diastolic function including speckle tracking derived strain were performed. Patients were grouped according to fibril type and sex. Multivariate linear regression was utilised to determine factors of significant impact on LV thickness.

Results

There was no significant difference in proportions of the two types of fibrils between men and women. In patients with type A fibrils, women had significantly lower median septal (p = 0.007) and posterior wall thicknesses (p = 0.010), lower median LV mass indexed to height (p = 0.008), and higher septal strain (p = 0.037), as compared to males. These differences were not apparent in patients with type B fibrils. Multiple linear regression analysis revealed that fibril type, sex and age all had significant impact on LV septal thickness.

Conclusion

This study demonstrates a clear difference between sexes in the severity of amyloid heart disease in ATTR V30M amyloidosis patients. Even though type A fibrils were associated with more advanced amyloid heart disease compared to type B, women with type A fibrils generally developed less cardiac infiltration than men. The differences may explain the better outcome for liver transplanted late-onset female patients compared to males.

Effects of biological sex on the pathophysiology of the heart

Cardiovascular diseases are the leading causes of death in men and women in industrialized countries. While the effects of biological sex on cardiovascular pathophysiology have long been known, the sex-specific mechanisms mediating these processes have been further elucidated over recent years. This review aims at analysing the sex-based differences in cardiac structure and function in adult mammals, and the sex-based differences in the main molecular mechanisms involved in the response of the heart to pathological situations. It emerged from this review that the sex-based difference is a variable that should be dealt with, not only in basic science or clinical research, but also with regards to therapeutic approaches.

Gender difference in the relation blood pressure-left ventricular mass and geometry in newly diagnosed arterial hypertension

Much evidence suggests sexual dimorphism in the relationship linking blood pressure (BP) to both left ventricular mass (LVM) and geometry in hypertension. To better evaluate gender-associated characteristics in the relation BP-LVM among newly diagnosed hypertension (24-h average ambulatory BP monitoring, ABPM, > 125/80 mmHg), we measured indexed LVM and relative wall thickness (RWT) by standardized echographic methods in 209 Caucasian drug-naïve subjects, of whom 162 (100M/62F) were recognized to be hypertensive. Mean office systolic (SBP)/diastolic (DBP), 24-h average and night-time BP values were similar between sexes and significantly related to indexed LVM in both genders. Daytime SBP was significantly related to indexed LVM only in females (r =0.41; p =0.0008 in women; r =0.11; p = NS in males), while LVM was more sensitive to day-to-night SBP change in females. RWT was, on the contrary, significantly related to ABPM values only in males. All these findings were confirmed after adjusting for possible confounders. Percentage of LVM variance explained by 24-h average, daytime or night-time SBP values were higher in females than in males (17% vs 3%; 11% vs 1%; and 17% vs 8%). In conclusion, in early hypertension, LVM was significantly associated with daytime BP and more sensitive to reduced percentage of night BP fall in females. LVM variance explained by ABPM SBP was much higher in females than in males. RWT, expressing concentric LVM remodelling was, conversely, more related to BP increase in males.

Elderly women with heart failure: unseen, unheard or simply forgotten?

In developed countries, cardiovascular disease is the leading cause of death among women; one-third of these deaths are directly or indirectly related to heart failure. Women already constitute the majority of heart failure patients and, given their longer life expectancy, the proportion of elderly women with heart failure is likely to increase further. These figures alone should make elderly women with heart failure a medical research and public health priority. On the contrary, they have received, and continue to receive, very little attention. Elderly women have been largely excluded from heart failure clinical trials and, compared with their male counterparts, are under-recognized and less intensively investigated and treated in clinical practice. Elderly women with heart failure are at increased risk for adverse outcomes because of higher comorbidity, psychological distress and socioeconomic disadvantage. Yet, they are often left alone to deal with these problems, which can negatively affect their ability to carry out basic self-care tasks.

Prevention of adverse cardiac remodeling to volume overload in female rats is the result of an estrogen-altered mast cell phenotype

Previously, we have reported sex differences in the cardiac remodeling response to ventricular volume overload whereby male and ovariectomized (OVX) female rats develop eccentric hypertrophy, and intact (Int) female rats develop concentric hypertrophy. In males, this adverse remodeling has been attributed to an initial cascade of events involving myocardial mast cell and matrix metalloproteinase activation and extracellular collagen matrix degradation. The objective of this study was to determine the effect of female hormones on this initial cascade. Accordingly, an aortocaval fistula (Fist) was created in 7-wk-old Int and OVX rats, which, together with sham-operated (sham) controls, were studied at 1, 3, and 5 days postsurgery. In Int-Fist rats, myocardial mast cell density, collagen volume fraction, endothelin (ET)-1, stem cell factor (SCF), and TNF-α remained at control levels or were minimally elevated throughout the study period. This was not the case in the OVX-Fist group, where the initial response included significant increases in mast cell density, collagen degradation, ET-1, SCF, and TNF-α. These events in the OVX-Fist group were abolished by prefistula treatment with a mast cell stabilizer nedocromil. Of note was the observation that ET-1, TNF-α, SCF, and collagen volume fraction values for the OVX-sham group were greater than those of the Int-sham group, suggesting that the reduction of female hormones alone results in major myocardial changes. We concluded that female hormone-related cardioprotection to the volume stressed myocardium is the result of an altered mast cell phenotype and/or the prevention of mast cell activation.

Tetrahydrobiopterin restores diastolic function and attenuates superoxide production in ovariectomized mRen2.Lewis rats

After oophorectomy, mRen2.Lewis rats exhibit diastolic dysfunction associated with elevated superoxide, increased cardiac neuronal nitric oxide synthase (nNOS) expression, and diminished myocardial tetrahydrobiopterin (BH₄) content, effects that are attenuated with selective nNOS inhibition. BH₄ is an essential cofactor of nNOS catalytic activity leading to nitric oxide production. Therefore, we assessed the effect of 4 wk BH₄ supplementation on diastolic function and left ventricular (LV) remodeling in oophorectomized mRen2.Lewis rats compared with sham-operated controls. Female mRen2.Lewis rats underwent either bilateral ovariectomy (OVX) (n = 19) or sham operation (n = 13) at 4 wk of age. Beginning at 11 wk of age, OVX rats were randomized to receive either BH₄ (10 mg/kg · d) or saline, whereas the sham rats received saline via sc mini-pumps. Loss of ovarian hormones reduced cardiac BH₄ when compared with control hearts; this was associated with impaired myocardial relaxation, augmented filling pressures, increased collagen deposition, and thickened LV walls. Additionally, superoxide production increased and nitric oxide decreased in hearts from OVX compared with sham rats. Chronic BH₄ supplementation after OVX improved diastolic function and attenuated LV remodeling while restoring myocardial nitric oxide release and preventing reactive oxygen species generation. These data indicate that BH₄ supplementation protects against the adverse effects of ovarian hormonal loss on diastolic function and cardiac structure in mRen2.Lewis rats by restoring myocardial NO release and mitigating myocardial O₂⁻ generation. Whether BH₄ supplementation is a therapeutic option for the management of diastolic dysfunction in postmenopausal women will require direct testing in humans.

Impact of gender on left ventricle function in postmenopausal women and age-matched men: analysis of echocardiographic parameters in healthy participants and patients with coronary artery disease

OBJECTIVE

Our aim was to evaluate the impact of gender on the diastolic function of the left ventricle in healthy men and women and in patients with coronary artery disease (CAD) without systolic impairment.

METHODS

We examined 67 healthy participants (34 men with a mean age of 51 +/- 13 y and ejection fraction [EF] of 62% +/- 3% and 33 women with a mean age of 53 +/- 11 y and EF of 63% +/- 3%; P = NS) and 60 patients with CAD (36 men with a mean age of 57 +/- 10 y and EF of 59% +/- 3% and 24 women with a mean age of 59 +/- 10 y and EF of 60% +/- 3%), paired with regard to age, heart rate, and medical treatment by transthoracic echocardiography with the assessment of mitral and pulmonary vein flow parameters, propagation of mitral filling waves, and tissue Doppler variables of mitral annulus motion (MAM). The impact of gender was assessed separately for the healthy participants and the CAD group.

RESULTS

In healthy participants, the velocity of mitral inflow early wave and the systolic velocity of the pulmonary vein flow were significantly higher in women than in men: 77 +/- 18 versus 65 +/- 19 cm/second (P < 0.05) and 64 +/- 14 versus 57 +/- 11 cm/second (P < 0.05), respectively. On the other hand, velocities of MAM in the atrial and systolic phases were higher in men than in women: 13 +/- 2 versus 12 +/- 2 cm/second and 11 +/- 2 versus 10 +/- 2 cm/second, respectively (P < 0.05). The opposite tendency was observed in the CAD group: the ratio of early mitral inflow velocity to atrial mitral inflow velocity was significantly higher in male patients (1.1 +/- 0.5 vs 0.8 +/- 0.2; P = 0.007) and there was a trend toward faster early wave propagation in men (40 +/- 9 vs 36 +/- 8 cm/s; P = 0.08).

CONCLUSIONS

Our data suggest more efficient early diastolic filling in postmenopausal women than in age-matched men in healthy participants but an opposite relationship in patients with CAD.

17beta-Estradiol modulates local cardiac renin-angiotensin system to prevent cardiac remodeling in the DOCA-salt model of hypertension in rats

Ventricular remodeling can play a detrimental role in the progression of cardiovascular diseases, leading to heart failure. The current study was designed to investigate the effects of 17beta-estradiol (E2) on cardiac remodeling. Cardiac fibrosis and hypertrophy were examined in deoxycorticosterone acetate (DOCA)-salt treated rats with chronic, six-week administration of two different doses of E2. Bilaterally ovariectomized (Ovex) female Sprague-Dawley rats were randomly assigned to one of the following groups: Ovex-control; Ovex-DOCA; Ovex-DOCA+low-dose E2 (1.66 microg/day); or Ovex-DOCA+high-dose E2 (2.38 microg/day). All DOCA-treated rats were uninephrectomized and drinking water was replaced by 0.15M NaCl solution for the remainder of the study period. DOCA-salt treatment resulted in a significant increase in blood pressure, which was not altered by estrogen replacement. Histological examinations revealed marked cardiac remodeling (both ventricular hypertrophy and interstitial fibrosis) with DOCA treatment, which was attenuated in animals receiving estrogen therapy. Western blot analysis demonstrated increased cardiac levels of angiotensin converting enzyme (ACE) with DOCA treatment, which was attenuated by E2 replacement. Furthermore, increased levels of cardiac angiotensin converting enzyme 2 (ACE2) protein were observed in animals receiving high-dose E2 replacement. These findings suggest that physiologically relevant estrogen replacement therapy has blood pressure-independent cardioprotective effects, which are possibly mediated through modulation of the cardiac renin-angiotensin system.

Magnetic resonance imaging left ventricular mass reduction with fixed-dose angiotensin-converting enzyme inhibitor-based regimens in patients with high-risk hypertension

Left ventricular hypertrophy, a major cardiovascular risk factor for morbidity and mortality, is commonly caused by arterial hypertension. The renin-angiotensin-aldosterone system may contribute to the pathogenesis of left ventricular hypertrophy. The Assessment of Lotrel in Left Ventricular Hypertrophy and Hypertension Study compared a single-pill combination of amlodipine/benazepril at doses 5.0/20.0 mg, 5.0/40.0 mg, and 10.0/40.0 mg with hydrochlorothiazide/benazepril at doses 12.5/20.0 mg, 12.5/40.0 mg, and 25.0/40.0 mg on the reduction of left ventricular mass index measured by cardiac MRI in stage 2 hypertensive patients over 52 weeks of treatment in a randomized clinical trial. A total of 125 male and female patients, > or =55 years of age, with echocardiographic left ventricular hypertrophy and high-risk hypertension defined as blood pressure > or =160/100 mm Hg or current antihypertensive treatment were enrolled. After 52 weeks of treatment, left ventricular mass index was significantly reduced from baseline with amlodipine/benazepril (mean: 10.16 g/m(2)) or hydrochlorothiazide/benazepril (mean: 6.74 g/m(2); both P<0.0001), with a mean difference between treatment groups of 3.36 g/m(2) (P=0.16). No significant treatment differences were observed in subgroups defined by age, male gender, race, diabetes status, or dose level. However, in female patients, left ventricular mass index reduction was greater with amlodipine/benazepril (P=0.02). Both treatments were well tolerated.

Chromosome Y variants from different inbred mouse strains are linked to differences in the morphologic and molecular responses of cardiac cells to postpubertal testosterone

BACKGROUND

We have reported previously that when chromosome Y (chrY) from the mouse strain C57BL/6J (ChrYC57) was substituted for that of A/J mice (ChrYA), cardiomyocytes from the resulting "chromosome substitution" C57BL/6J-chrYA strain were smaller than that of their C57BL/6J counterparts. In reverse, when chrYA from A/J mice was substituted for that of chrYC57, cardiomyocytes from the resulting A/J-chrYC57 strain were larger than in their A/J counterparts. We further used these strains to test whether: 1) the origin of chrY could also be linked to differences in the profile of gene expression in the hearts of adult male mice, and 2) post-pubertal testosterone could play a role in the differential morphologic and/or molecular effects of chrYC57 and chrYA.

RESULTS

The increased size of cardiomyocytes from adult male C57BL/6J mice compared to C57BL/6J-chrYA resulted from the absence of hypertrophic effects of post-pubertal testosterone on cells from the latter strain. However, gene profiling revealed that the latter effect could not be explained on the basis of an insensitivity of cells from C57BL/6J-chrYA to androgens, since even more cardiac genes were affected by post-pubertal testosterone in C57BL/6J-chrYA hearts than in C57BL/6J. By testing for interaction between the effects of surgery and strain, we identified 249 "interaction genes" whose expression was affected by post-pubertal testosterone differentially according to the genetic origin of chrY. These interaction genes were found to be enriched within a limited number of signaling pathways, including: 1) p53 signaling, which comprises the interacting genes Ccnd1, Pten and Cdkn1a that are also potential co-regulators of the androgen receptors, and 2) circadian rhythm, which comprises Arntl/Bmal1, which may in turn regulate cell growth via the control of Cdkn1a.

CONCLUSION

Although post-pubertal testosterone increased the size of cardiomyocytes from male C56BL/6J mice but not that from their C57BL/6J-chrYA counterparts, it affected gene expression in the hearts from both strains. However, several cardiac genes responded to post-pubertal testosterone in a strict strain-selective manner, which provides possible mechanisms explaining how chrY may, in part via interference with androgen regulatory events, be linked to morphologic differences of cardiac cells of adult male mice.

K(ATP) activation prevents progression of cardiac hypertrophy to failure induced by pressure overload via protecting endothelial function

AIMS

We investigated the effects of iptakalim, a new ATP-sensitive potassium channel (K(ATP)) opener providing endothelial protection, on the progression of cardiac hypertrophy to failure in a rat model of pressure overloading caused by abdominal aortic banding (AAB). Endothelial dysfunction is central to cardiac hypertrophy and failure induced by pressure overload. It would be useful to clarify whether iptakalim could prevent this.

METHODS AND RESULTS

The effects of pressure overload were assessed in male Sprague-Dawley rats 6 weeks after AAB using progression of cardiac hypertrophy to heart failure as the endpoint. The AAB-treated rats had significantly elevated blood pressure, systolic and diastolic cardiac dysfunction, evidence of left ventricular hypertrophy (LVH), and transition to heart failure. LVH was characterized by increases in the ratios of heart and left ventricular weights to body weight, increased myocyte cross-sectional areas, myocardial and perivascular fibrosis, and elevated cardiac hydroxyproline. These could be prevented by treatment with iptakalim at daily oral doses of 1, 3, and 9 mg/kg for 6 weeks. Progression to cardiac failure, demonstrated by increases in relative lung and right ventricular weights, cardiac function disorders and overexpression of atrial and B-type natriuretic peptide mRNA, could also be prevented. The downregulated nitric oxide signalling system was enhanced, whereas the upregulated endothelin signalling system was inhibited, resulting in normalization of the balance between these two systems.

CONCLUSION

Iptakalim protected the endothelium and prevented progression of cardiac hypertrophy to failure induced by a pressure overload.

Sex and age dimorphism of myocardial gene expression in nonischemic human heart failure

BACKGROUND

We report the first comprehensive analysis of gene expression differences by sex and age in left ventricular samples from 102 patients with dilated cardiomyopathy.

METHODS AND RESULTS

Gene expression data (HG-U133A gene chip, Affymetrix) were analyzed from 30 females and 72 males from 3 separate centers. More than 1800 genes displayed sexual dimorphism in the heart (adjusted P value <0.05). A significant number of these genes were highly represented in gene ontology pathways involved in ion transport and G-protein-coupled receptor signaling. Localization of these genes revealed enrichment on both the sex chromosomes as well as chromosomes 3, 4, and 14. The second goal of this study was to determine the effect of age on gene expression. Within the female cohort, >140 genes were differentially expressed in the <55 years age group compared with the >55 years age group. These genes were highly represented in gene ontology pathways involved in DNA damage. In contrast, zero genes in the male cohort <55 years met statistical significance when compared with the >55 years age group.

CONCLUSIONS

Gene expression in dilated cardiomyopathy displayed evidence of sexual dimorphism similar to other somatic tissues and age dimorphism within the female cohort.

Deoxycorticosterone Acetate-Salt Mice Exhibit Blood Pressure–Independent Sexual Dimorphism

We tested the hypothesis that female and male mice differ in terms of cardiac hypertrophy after deoxycorticosterone acetate (DOCA)+salt hypertension (uninephrectomy and 1% saline in drinking water) and focused on calcineurin signaling. We excluded confounding effects of blood pressure elevation or sex-related blood pressure differences by treating DOCA-salt mice with hydralazine (250 mg/L in drinking water). We found that directly measured mean arterial blood pressure was lowered to control values with hydralazine and corroborated this finding in separate mouse groups with radiotelemetry. Male mice were more responsive to DOCA-salt–related effects. They developed more left ventricular hypertrophy and more renal hypertrophy after 6 weeks of DOCA-salt+hydralazine compared with female mice. In hearts, transcripts for calcineurin Aβ and for myocyte-enriched calcineurin interacting protein 1 were upregulated in male but not in female mice. Enhanced activity of calcineurin Aβ, as indicated by diminished phosphorylation of NFATc2 in male mice, accounted for this sex-specific difference. Stretch-related, inflammatory, and profibrotic responses were also accentuated in male mice, as shown by higher transcript levels of atrial natriuretic peptide, monocyte chemoattractant protein-1, and transforming growth factor-β. Our results support sex-specific regulation of the calcineurin pathway in response to largely blood pressure–independent mineralocorticoid action. We suggest that sex-specific calcineurin activation determines the maladaptive cardiac and renal hypertrophic responses and accompanying organ injury in male mice.

Mechanisms of cardiac fibrosis in hypertension

Changes in the composition of cardiac tissue develop in hypertensive patients with left ventricular hypertrophy (ie, hypertensive heart disease) and lead to structural remodeling of the myocardium. One of these changes is related to the disruption of the equilibrium between the synthesis and degradation of collagen types I and III molecules, which results in an excessive accumulation of collagen types I and III fibers within the myocardium. Myocardial fibrosis is the consequence of a number of pathologic processes mediated by mechanical, neurohormonal, and cytokine routes. The clinical relevance of fibrosis is that it may contribute to heart failure and other cardiac complications in patients with hypertensive heart disease. This brief review focuses on the mechanisms of hypertensive myocardial fibrosis.

Cardiac mass and cardiomyocyte size are governed by different genetic loci on either autosomes or chromosome Y in recombinant inbred mice

Left ventricular hypertrophy is one of the main risk factors for cardiovascular mortality and morbidity. It has been proposed that hypertrophic stimuli act in great part by increasing the size of cardiomyocytes, and that the latter characteristic is a necessary condition to differentiate left ventricular hypertrophy from other benign forms of cardiac enlargement. To test whether the same genetic loci control the size of cardiomyocytes and left ventricular mass, we performed whole genome linkage analyses in a panel of 24 recombinant inbred AXB/BXA mouse strains. Whereas one major locus was linked to left ventricular mass in both males and females, loci linked to the size of cardiomyocytes were clearly distinct and showed sex-specific linkage. Moreover, the parental origin of chromosome Y had strong effects on the size of cardiomyocytes in male mice but did not affect left ventricular mass. In addition to showing that genetic loci that increase the size of cardiomyocytes are not necessarily linked to increased left ventricular mass, our findings have important consequences in evaluating cardiac phenotypes when performing genetic manipulations in mice, and in determining the cause of sex-specific differences when using models derived from C57BL/6J mice.