Gender issues in cardiovascular diseases. Focus on energy metabolism

Extracellular Matrix Instability and Chronic Inflammation Underlie Maladaptive Right Ventricular Pressure Overload Remodeling and Failure in Male Mice

Background

Right ventricular dysfunction (RVD) portends increased death risk for heart failure (HF) and pulmonary arterial hypertension (PAH) patients, regardless of left ventricular function or etiology. In both, RVD arises from the chronic RV pressure overload, and represents advanced cardiopulmonary disease. RV remodeling responses and survival rates of HF and PAH patients, however, differ by sex. Men develop more severe RVD and die at younger ages than do women. Mechanistic details of this sexual dimorphism in RV remodeling are incompletely understood. We sought to elucidate the cardiac pathophysiology underlying the sex-specific RV remodeling phenotypes, RV failure (RVF) versus compensated RVD.

Methods

We subjected male (M-) and female (F-) adult mice to moderate pulmonary artery banding (PAB) for 9wks. Mice underwent serial echocardiography, cardiac MRI, RV pressure-volume loop recordings, histologic and molecular analyses.

Results

M-PAB developed severe RVD with RVF, increased RV collagen deposition and degradation, extracellular matrix (ECM) instability, and activation and recruitment of macrophages. Despite the same severity and chronicity of RV pressure overload, F-PAB had more stable ECM, lacked chronic inflammation, and developed mild RVD without RVF.

Conclusions

ECM destabilization and chronic activation of recruited macrophages are associated with maladaptive RV remodeling and RVF in male PAB mice. Adaptive RV remodeling of female PAB mice lacked these histopathologic changes. Our findings suggest that these two pathophysiologic processes likely contribute to the sexual dimorphism of RV pressure overload remodeling. Further mechanistic studies are needed to assess their pathogenic roles and potential as targets for RVD therapy and RVF prevention.

CLINICAL PERSPECTIVE

What is new?: In a mouse model of pure PH, males but not females showed an association between ECM instability, chronic inflammation with activation of recruited macrophages, and severe RV dysfunction and failure.What are the clinical implications?: In male HF and PH patients, enhancing ECM stability and countering the recruitment and activation of macrophages may help preserve RV function such that RVF can be prevented or delayed. Further preclinical mechanistic studies are needed to assess the therapeutic potential of such approaches.

RESEARCH PERSPECTIVE

What new question does this study raise? What question should be addressed next?: What mechanisms regulate RV ECM stability and macrophage recruitment and activation in response to chronic RV pressure overload? Are these regulatory mechanisms dependent upon or independent of sex hormone signaling?

Gender Effect on Clinical Profiles, Pharmacological Treatments and Prognosis in Patients Hospitalized for Heart Failure

Heart failure (HF) is a significant disease affecting 1-2% of the general population. Despite its general aspects, HF, like other cardiovascular diseases, presents various gender-specific aspects in terms of etiology, hemodynamics, clinical characteristics, therapy, and outcomes. As is well known, HF with preserved ejection fraction more frequently affects females, with diabetes and arterial hypertension representing the most critical determinants of HF. On the other hand, women are traditionally underrepresented in clinical trials and are often considered undertreated. However, it is not clear whether such differences reflect cultural behaviors and clinical inertia or if they indicate different clinical profiles and the impact of sex on hard clinical outcomes. We aimed to review the sex-related differences in patients affected by HF.

Association between renal surface nodularity and increased adverse vascular event risk in patients with arterial hypertension

OBJECTIVE

To explore the association of renal surface nodularity (RSN) with the increased adverse vascular event (AVE) risk in patients with arterial hypertension.

METHODS

This cross-sectional study included patients with arterial hypertension aged 18-60 years who underwent contrasted computed tomography (CT) of kidney from January 2012 to December 2020. The subjects were classified into AVE or not (non-AVE) matched with age (≤5 years) and sex. Their CT images were analyzed using both qualitative (semiRSN) and quantitative RSN (qRSN) methods, respectively. Their clinical characteristics included age, sex, systolic blood pressure (SBP), diastolic blood pressure, hypertension course, diabetes history, hyperlipidemia, and estimated glomerular filtration rate (eGFR).

RESULTS

Compared with non-AVE group (n = 91), AVE (n = 91) was at lower age, higher SBP, and fewer rate of diabetes and hyperlipidemia history (all P < .01). Rate of positive semiRSN was higher in AVE than non-AVE (49.45% vs 14.29%, P < .001). qRSN was larger in AVE than non-AVE [1.03 (0.85, 1.33) vs 0.86 (0.75,1.03), P < .001]. The increased AVE was associated with semiRSN (odds ratio = 7.04, P < .001) and qRSN (odds ratio = 5.09, P = .003), respectively. For distinguishing AVE from non-AVE, the area under receiver operating characteristic was bigger in the models combining the clinical characteristics with either semiRSN or qRSN than that of semiRSN or qRSN alone (P ≤.01).

CONCLUSION

Among the patients with arterial hypertension aged 18-60 years, CT imaging-based RSN was associated with increased AVE risk.

Male and Female Mitochondria Respond Differently after Exercising in Acute Hypoxia

The use of hypoxic devices among athletes who train in normobaric hypoxia has become increasingly popular; however, the acute effects on heart and brain metabolism are not yet fully understood. This study aimed to investigate the mitochondrial bioenergetics in trained male and female Wistar rats after acute hypoxia training. The experimental plan included exercising for 30 min on a treadmill in a Plexiglas cage connected to a hypoxic generator set at 12.5% O2 or in normoxia. After the exercise, the rats were sacrificed, and their mitochondria were isolated from their brains and hearts. The bioenergetics for each complex of the electron transport chain was tested using a Clark-type electrode. The results showed that following hypoxia training, females experienced impaired oxidative phosphorylation through complex II in heart subsarcolemmal mitochondria, while males had an altered ADP/O in heart interfibrillar mitochondria, without any change in oxidative capacity. No differences from controls were evident in the brain, but an increased electron transport system efficiency was observed with complex I and IV substrates in males. Therefore, the study's findings suggest that hypoxia training affects the heart mitochondria of females more than males. This raises a cautionary flag for female athletes who use hypoxic devices.

Effects of Gestational Hypoxia on PGC1α and Mitochondrial Acetylation in Fetal Guinea Pig Hearts

Chronic intrauterine hypoxia is a significant pregnancy complication impacting fetal heart growth, metabolism, and mitochondrial function, contributing to cardiovascular programming of the offspring. PGC1α (peroxisome proliferator-activated receptor γ co-activator 1α) is the master regulator of mitochondrial biogenesis. We investigated the effects of hypoxia on PGC1α expression following exposure at different gestational ages. Time-mated pregnant guinea pigs were exposed to normoxia (NMX, 21% O2) or hypoxia (HPX, 10.5% O2) at either 25-day (early-onset) or 50-day (late-onset) gestation, and all fetuses were extracted at term (term = ~65-day gestation). Expression of nuclear PGC1α, sirtuin 1 (SIRT1), AMP-activated protein kinase (AMPK), and mitochondrial sirtuin 3 (SIRT3) was measured, along with SIRT3 activity and mitochondrial acetylation of heart ventricles of male and female fetuses. Early-onset hypoxia increased (P<0.05) fetal cardiac nuclear PGC1α and had no effect on mitochondrial acetylation of either growth-restricted males or females. Late-onset hypoxia had either no effect or decreased (P<0.05) PCC1α expression in males and females, respectively, but increased (P<0.05) mitochondrial acetylation in both sexes. Hypoxia had variable effects on expression of SIRT1, AMPK, SIRT3, and SIRT3 activity depending on the sex. The capacity of the fetal heart to respond to hypoxia differs depending on the gestational age of exposure and sex of the fetus. Further, the effects of late-onset hypoxia on fetal heart function impose a greater risk to male than female fetuses, which has implications toward cardiovascular programming effects of the offspring.

Addressing Cardiovascular Risk Across the Arc of a Woman's Life: Sex-Specific Prevention and Treatment

PURPOSE OF REVIEW

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in women in the United States of America. Despite this, women are underdiagnosed, less often receive preventive care, and are undertreated for CVD compared to men. There has been an increase in sex-specific risk factors and treatments over the past decade; however, sex-specific recommendations have not been included in the guidelines. We aim to highlight recent evidence behind the differential effect of traditional risk factors and underscore sex-specific risk factors with an intention to promote awareness, improve risk stratification, and early implementation of appropriate preventive therapies in women.

RECENT FINDINGS

Women are prescribed fewer antihypertensives and lipid-lowering agents and receive less cardiovascular care as compared to men. Additionally, pregnancy complications have been associated with increased cardiovascular mortality later in life. Findings from the ARIC study suggest that there is a perception of lower risk of cardiovascular disease in women. The SWEDEHEART study which investigated sex differences in treatment, noted a lower prescription of guideline-directed therapy in women. Women are less likely to be prescribed statin medications by their providers in both primary and secondary prevention as they are considered lower risk than men, while also being more likely to decline and discontinue treatment. A woman's abnormal response to pregnancy may serve as her first physiological stress test which can have implications on her future cardiovascular health. This was supported by the CHAMPs study noting a higher premature cardiovascular risk after maternal complications. Adverse pregnancy outcomes have been associated with a 1.5-4.0 fold increase in future cardiovascular events in multiple studies. In this review, we highlight the differences in traditional risk factors and their impact on women. Furthermore, we address the sex-specific risk factors and pregnancy-associated complications that increase the risk of CVD in women. Adherence to GDMT may have implications on overall mortality in women. An effort to improve early recognition of CVD risk with implementation of aggressive risk factor control and lifestyle modification should be emphasized. Future studies should specifically report on differences in outcomes between males and females. Increased awareness and knowledge on sex-specific risks and prevention are likely to lower the prevalence and improve outcomes of CVD in women.

Knowledge, attitudes, and beliefs of cardiovascular disease prevention in young adults in the country of Georgia

INTRODUCTION

Cardiovascular disease (CVD) accounts for 46% of all mortality in the country of Georgia (former Soviet Union). Young adults in that country have not been studied regarding CVD and a need exists to understand lifestyle modifications to promote cardiovascular health.

DESIGN

An interpretive description qualitative design was used to explore Georgian young adults' knowledge, attitudes, and beliefs of CVD preventative practices and life experiences.

METHODS

A convenience sample of 19 ethnic Georgian participants (18-40 years old) who were fluent in either English, Georgian, or Russian from a local private university was used. Semi-structured interviews were conducted via video conferencing utilizing an interpreter.

RESULTS

Four themes were identified: (1) CVD and risk factor knowledge, (2) prevention attitudes, beliefs, and gender differences, (3) health literacy influences, and (4) culture and societal impacts. CVD knowledge was limited and influenced by health literacy and the current healthcare system in Georgia.

CONCLUSION

Cultural and societal gender norms influence cardiovascular health behaviors.

CLINICAL IMPLICATIONS

Georgian nurses can play a key role in CVD education and screening for young adults in Georgia.

Sex differences matter: Males and females are equal but not the same

Sex differences between males and females can be detected early in life. They are present also later even to a much greater extent affecting our life in adulthood and a wide spectrum of physical, psychological, cognitive, and behavioral characteristics. Moreover, sex differences matter also in individual's health and disease. In this article, we reviewed at first the sex differences in brain organization and function with respect to the underlying biological mechanisms. Since the individual functional differences in the brain, in turn, shape the behavior, sex-specific psychological/behavioral differences that can be observed in infants but also adults are consequently addressed. Finally, we briefly mention sex-dependent variations in susceptibility to selected disorders as well as their pathophysiology, diagnosis, and response to therapy. The understanding of biologically determined variability between males and females can have important implications, especially in gender-specific health care. We have the impression that it is very important to emphasize that sex matters. Males and females are differently programmed by nature, and it must be respected. Even though we as males and females are not the same, we would like to emphasize that we are still equal and together form a worthy colorful continuum.

Circadian regulation of genetic and hormonal risk factors of cardiovascular disease in women

Cardiovascular disease is the leading cause of morbidity and mortality worldwide. However, sex differences can impact differently the etiology and outcome of cardiovascular disease when comparing men and women. Women have unique genetic and hormonal risk factors that can be associated with the development of cardiovascular diseases. Furthermore, certain phenotypes of cardiovascular diseases are more prevalent to women. Molecular clocks control circadian rhythms of different physiological systems in our body, including the cardiovascular system. Increased evidence in recent years points to a link between cardiovascular disease and regulation by circadian rhythms. However, the difference between circadian regulation of cardiovascular disease in women and men is poorly understood. In this review, we highlight the recent advances in circadian-regulated cardiovascular diseases with a specific focus on the pathogenesis of heart disease in women. Understanding circadian-regulated pathways and sex-specific differences between men and women may contribute to better diagnosis and development of sex-targeted interventions to better treat cardiovascular diseases.

Sex as Biological Variable in Cardiac Mitochondrial Bioenergetic Responses to Acute Stress

Cardiac dysfunction/damage following trauma, shock, sepsis, and ischemia impacts clinical outcomes. Acute inflammation and oxidative stress triggered by these injuries impair mitochondria, which are critical to maintaining cardiac function. Despite sex dimorphisms in consequences of these injuries, it is unclear whether mitochondrial bioenergetic responses to inflammation/oxidative stress are sex-dependent. We hypothesized that sex disparity in mitochondrial bioenergetics following TNFα or H2O2 exposure is responsible for reported sex differences in cardiac damage/dysfunction. Methods and Results: Cardiomyocytes isolated from age-matched adult male and female mice were subjected to 1 h TNFα or H2O2 challenge, followed by detection of mitochondrial respiration capacity using the Seahorse XF96 Cell Mito Stress Test. Mitochondrial membrane potential (ΔΨm) was analyzed using JC-1 in TNFα-challenged cardiomyocytes. We found that cardiomyocytes isolated from female mice displayed a better mitochondrial bioenergetic response to TNFα or H2O2 than those isolated from male mice did. TNFα decreased ΔΨm in cardiomyocytes isolated from males but not from females. 17β-estradiol (E2) treatment improved mitochondrial metabolic function in cardiomyocytes from male mice subjected to TNFα or H2O2 treatment. Conclusions: Cardiomyocyte mitochondria from female mice were more resistant to acute stress than those from males. The female sex hormone E2 treatment protected cardiac mitochondria against acute inflammatory and oxidative stress.

Sex as a Biological Variable in Cardiovascular Diseases: JACC Focus Seminar 1/7

Sex and gender influence all aspects of cardiovascular health and disease-including epidemiology, pathophysiology, diagnosis, clinical manifestation, disease progression, and response to treatment-in complex and interrelated ways. Sex-based and gender-based differences have been identified in risk and presentation of cardiovascular diseases (CVDs); however, failure to address sex and gender as key variables in CVD research and reporting and limited understanding of differences have contributed to disparities in risk assessment, prevention, diagnosis, treatment, and outcomes. Improved consideration of both sex and gender in all phases of the biomedical research continuum, along with educational and training curricula focused on the role of sex and gender in CVD, are needed to provide targeted therapies and improve cardiovascular health outcomes for all.

Metabolic Syndrome and β-Oxidation of Long-Chain Fatty Acids in the Brain, Heart, and Kidney Mitochondria

We present evidence that metabolic syndrome (MetS) represents the postreproductive stage of the human postembryonic ontogenesis. Accordingly, the genes governing this stage experience relatively weak evolutionary selection pressure, thus representing the metabolic phenotype of distant ancestors with β-oxidation of long-chain fatty acids (FAs) as the primary energy source. Mitochondria oxidize at high-rate FAs only when succinate, glutamate, or pyruvate are present. The heart and brain mitochondria work at a wide range of functional loads and possess an intrinsic inhibition of complex II to prevent oxidative stress at periods of low functional activity. Kidney mitochondria constantly work at a high rate and lack inhibition of complex II. We suggest that in people with MetS, oxidative stress is the central mechanism of the heart and brain pathologies. Oxidative stress is a secondary pathogenetic mechanism in the kidney, while the primary mechanisms are kidney hypoxia caused by persistent hyperglycemia and hypertension. Current evidence suggests that most of the nongenetic pathologies associated with MetS originate from the inconsistencies between the metabolic phenotype acquired after the transition to the postreproductive stage and excessive consumption of food rich in carbohydrates and a sedentary lifestyle.

Essential amino acid formulations to prevent mitochondrial dysfunction and oxidative stress

PURPOSE OF REVIEW

Both restriction and supplementation of specific amino acids or branched-chain amino acids (BCAAs) are described to improve metabolic homeostasis, energy balance, and health span. This review will discuss the recent findings of the role of amino acid supplements in the regulation of mitochondrial health.

RECENT FINDINGS

A mixture of essential amino acids (EAAs), BCAA enriched mixture, was found to extend healthy life span in elderly mice and prevent multiple diseases associated with an energy deficit, similarly to caloric restriction or fasting-mimicking diets. A growing body of evidence highlights mitochondria as the central target of this supplement: it promotes mitochondrial biogenesis and the activation of antioxidant defence systems in different physiological (e.g., exercise or ageing) or pathological conditions (e.g., sarcopenia, muscular dystrophy, liver steatosis, or impaired cognition). Based on these results, new formulas have been created enriched with Krebs cycle substrates, behaving more efficiently than BCAA enriched mixture.

SUMMARY

EAA-BCAA balanced supplements might be valuable not only for healthy individuals undergoing to energy deficit (e.g., athletes) during strenuous exercise or training but also against diseases characterized by a dysregulated catabolic state or mitochondrial dysfunction, such as age-related disorders. The associated mechanistic processes should be identified as potential pharmacological targets.