The Aging Heart

H2S Donor SPRC Ameliorates Cardiac Aging by Suppression of JMJD3, a Histone Demethylase

Aims: S-propargyl-cysteine (SPRC) is an endogenous hydrogen sulfide (H2S) donor obtained by modifying the structure of S-allyl cysteine in garlic. This study aims to investigate the effect of SPRC on mitigating cardiac aging and the involvement of jumonji domain-containing protein 3 (JMJD3), a histone demethylase, which represents the primary risk factor in major aging related diseases, in this process, elucidating the preliminary mechanism through which SPRC regulation of JMJD3 occurs. Results: In vitro, SPRC mitigated the elevated levels of reactive oxygen species, senescence-associated β-galactosidase, p53, and p21, reversing the decline in mitochondrial membrane potential, which represented a reduction in cellular senescence. In vivo, SPRC improved Dox-induced cardiac pathological structure and function. Overexpression of JMJD3 accelerated cardiomyocytes and cardiac senescence, whereas its knockdown in vitro reduced the senescence phenotype. The potential binding site of the upstream transcription factor of JMJD3, sheared X box binding protein 1 (XBP1s), was determined using online software. SPRC promoted the expression of cystathionine γ-lyase (CSE), which subsequently inhibited the IRE1α/XBP1s signaling pathway and decreased JMJD3 expression. Innovations: This study is the first to establish JMJD3 as a crucial regulator of cardiac aging. SPRC can alleviate cardiac aging by upregulating CSE and inhibiting endoplasmic reticulum stress pathways, which in turn suppress JMJD3 expression. Conclusions: JMJD3 plays an essential role in cardiac aging regulation, whereas SPRC can suppress the expression of JMJD3 by upregulating CSE, thus delaying cardiac aging, which suggests that SPRC may serve as an aging protective agent, and pharmacological targeting of JMJD3 may also be a promising therapeutic approach in age-related heart diseases. Antioxid. Redox Signal. 42, 301-320.

Urolithin A provides cardioprotection and mitochondrial quality enhancement preclinically and improves human cardiovascular health biomarkers

Cardiovascular diseases (CVDs) remain the primary cause of global mortality. Nutritional interventions hold promise to reduce CVD risks in an increasingly aging population. However, few nutritional interventions are proven to support heart health and act mostly on blood lipid homeostasis rather than at cardiac cell level. Here, we show that mitochondrial quality dysfunctions are common hallmarks in human cardiomyocytes upon heart aging and in chronic conditions. Preclinically, the post-biotic and mitophagy activator, urolithin A (UA), reduced both systolic and diastolic cardiac dysfunction in models of natural aging and heart failure. At a cellular level, this was associated with a recovery of mitochondrial ultrastructural defects and mitophagy. In humans, UA supplementation for 4 months in healthy older adults significantly reduced plasma ceramides clinically validated to predict CVD risks. These findings extend and translate UA's benefits to heart health, making UA a promising nutritional intervention to support cardiovascular function as we age.

Evolutionary Insights into Irisin/FNDC5: Roles in Aging and Disease from Drosophila to Mammals

The Irisin/FNDC5 protein family has emerged as a pivotal link between exercise and the prevention of age-associated diseases. Irisin is highly expressed during exercise from skeletal and cardiac muscle cells, playing a critical role in mediating systemic health benefits through its actions on various tissues. However, Irisin levels decline with age, correlating with a heightened incidence of diseases such as muscle weakness, cardiovascular disorders, and neurodegeneration. Notably, the administration of Irisin has shown significant potential in both preventing and treating these conditions. Recently, an Irisin/FNDC5 homolog was identified in an invertebrate Drosophila model, providing valuable insights into its conserved role in exercise physiology. Importantly, Irisin/FNDC5 has been demonstrated to regulate autophagy-a process essential for clearing excessive nutrients, toxic aggregates, and dysfunctional organelles-in both flies and mammals. Dysregulated autophagy is often implicated in age-related diseases, highlighting its relevance to Irisin/FNDC5's functions. These findings deepen our understanding of Irisin/FNDC5's roles and its potential as a therapeutic target for mitigating aging-related health decline. Further studies are needed to elucidate the precise mechanisms by which Irisin regulates autophagy and its broader impact on physiological aging and related diseases.

Senolytics rejuvenate aging cardiomyopathy in human cardiac organoids

BACKGROUND

Human cardiac organoids closely replicate the architecture and function of the human heart, offering a potential accurate platform for studying cellular and molecular features of aging cardiomyopathy. Senolytics have shown potential in addressing age-related pathologies but their potential to reverse aging-related human cardiomyopathy remains largely unexplored.

METHODS

We employed human iPSC-derived cardiac organoids (hCOs/hCardioids) to model doxorubicin(DOXO)-induced cardiomyopathy in an aged context. hCardioids were treated with DOXO and subsequently with a combination of two senolytics: dasatinib (D) and quercetin (Q).

RESULTS

DOXO-treated hCardioids exhibited significantly increased oxidative stress, DNA damage (pH2AX), cellular senescence (p16INK4A) and decreased cell proliferation associated with a senescence-associated secretory phenotype (SASP). DOXO-treated hCardioids were considerably deprived of cardiac progenitors and displayed reduced cardiomyocyte proliferation as well as contractility. These distinctive aging-associated characteristics were confirmed by global RNA-sequencing analysis. Treatment with D+Q reversed these effects, reducing oxidative stress and senescence markers, alleviating SASP, and restoring hCardioids viability and function. Additionally, senolytics replenished cardiac progenitors and reversed the cardiomyocyte proliferation deficit.

CONCLUSIONS

Doxorubicin triggers an age-associated phenotype in hCardioids reliably modelling the main cellular and molecular features of aging cardiomyopathy. Senescence is a key mechanism of the aged-hCOs phenotype as senolytics rejuvenated aged-hCardioids restoring their structure and function while reverting the age-associated regenerative deficit.

Acute GLP-1 Agonism Induces Arrhythmogenic Electrical Activity in Aged Mice Heart Through Impaired Cellular Na+ and Ca2+ Handlings: The Role of CK2 Hyperphosphorylation

BACKGROUND

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are known for their benefits in conditions like cardiovascular diseases in type 2 diabetes and obesity. They also show promise for aging-related conditions with minimal side effects. However, their impact on cardiovascular risk is still debated. Notably, some long-acting GLP-1RAs cause a sustained increase in heart rate on the first day of use without a clear mechanism. To understand their short-term effects, we examined acute GLP-1R agonism on the electrical activity of elderly hearts.

METHODS

In this study, we utilized in vivo electrocardiography, in vitro cellular electrophysiology experiments, and biochemical measurements on heart preparations from 6-month-old (Adult) and 24-month-old (aged) BALB/c mice.

RESULTS

A single liraglutide injection (0.3 mg/kg) induced repetitive, self-sustained arrhythmogenic electrocardiograms in aged mice (24 months old) but had no effect on adults (6 months old) within the first 10 minutes. Acute application of liraglutide to isolated ventricular cardiomyocytes from aged mice significantly prolonged the late phase of action potential repolarization (APR90). This was due to suppressed K+ currents and increased persistent Na+currents (Late-INa), primarily through delayed recovery from inactivation of Na+ currents. Additionally, liraglutide increased Ca2+ spark frequency and wave formation by enhancing Ca2+ release from the sarcoplasmic reticulum, affecting both Na+ and Ca2+ regulation in aging cells. Liraglutide also induced casein kinase 2 (CK2) hyperphosphorylation in aged cardiomyocytes, which a CK2 inhibitor could reverse, normalizing APR90 by reducing Late-INa and enhancing K+ currents.

CONCLUSION

These findings reveal that acute GLP-1R agonism can disrupt electrical signaling and induce arrhythmia in aged mice through CK2 hyperphosphorylation, providing new insights into the cardiovascular effects of GLP-1RAs in the elderly.

Mouse models used to test the role of reactive oxygen species in aging and age-related chronic diseases

With the development of the technology to generate transgenic and knockout mice in the 1990s, investigators had a powerful tool to directly test the impact of altering a specific gene on a biological process or disease. Over the past three decades, investigators have used transgenic and knockout mouse models, which have altered expression of antioxidant genes, to test the role of oxidative stress/damage in aging and age-related diseases. In this comprehensive review, we describe the studies using transgenic and knockout mouse models to test the role of oxidative stress/damage in aging (longevity) and three age-related diseases, e.g., sarcopenia, cardiac aging, and Alzheimer's Disease. While longevity was consistently altered only by one transgenic and one knockout mouse model as predicted by the Oxidative Stress Theory of Aging, the incidence/progression of the three age-related diseases (especially Alzheimer's disease) were robustly impacted when the expression of various antioxidant genes was altered using transgenic and knockout mouse models.

Olive oil protects against cardiac hypertrophy in D-galactose induced aging rats

BACKGROUND

Aged heart is defined via structural and mitochondrial dysfunction of the heart. However, there is still no potent compound to improve cardiac function abnormalities in aged individuals. Olive oil (OLO), as an oil with monounsaturated fatty acids, has diverse protective effects on the cardiovascular system, including anti-inflammatory, anti-diabetic, and mitigating effects on blood pressure. In the present study, we evaluated the protective effects of OLO against aging-related cardiac dysfunction.

METHODS

Male Wistar rats were randomly divided into three groups: Control, D-galactose-induced aging rats (D-GAL group), and aging rats treated with OLO (D-GAL + OLO group). Aging in rats was induced by intraperitoneal injection of D-GAL at 150 mg/kg dose for eight weeks and the D-GAL + OLO group was treated with oral OLO by gavage for eight weeks. The heart tissues were harvested to assay the oxidative stress, molecular parameters, and histological analysis.

RESULTS

The D-GAL given rats indicated increased cardiomyocyte diameter as cardiac hypertrophy marker (21 ± 0.8, p < 0.001), an increased Malondialdehyde (MDA) level (27 ± 3, p < 0.001), a reduced Superoxide dismutase (SOD) (p < 0.001, 18.12 ± 1.3), and reduction in gene expression of Sirtuin 1 (SIRT1) (p < 0.05, 0.37 ± 0.06), Peroxisome proliferator-activated receptor-gamma coactivator (PGC)-1α (p < 0.001, 0.027 ± 0.04), and Transcription Factor A, Mitochondrial (TFAM) (p < 0.001, 0.023 ± 0.01), Bcl2 (p < 0.001, 0.04 ± 0.004) and an increase in gene expression of Bax (p < 0.001, 23.5 ± 5.4) in comparison with the control animals. Treatment with OLO improved cardiac hypertrophy (14 ± 0.4, p < 0.001), MDA (22 ± 2.5, p < 0.01), SOD (p < 0.001, 34.9 ± 2), SIRT1 (p < 0.05, 1.37 ± 0.46), PGC-1α (p < 0.001, 1.11 ± 0.1), TFAM (p < 0.01, 0.23 ± 0.02), Bcl2 (p < 0.05, 0.35 ± 0.05) and Bax genes (p < 0.01, 0.1 ± 0.03).

CONCLUSIONS

Overall, OLO protects the heart against D-GAL-induced aging via increasing antioxidant effects, and enhancing cardiac expression of SIRT1, PGC-1α, TFAM, Bcl2 and Bax genes.

Heart Failure with Preserved Ejection Fraction and Cardiac Amyloidosis in the Aging Heart

Heart Failure with Preserved Ejection Fraction (HFpEF) is one of the most frequent causes of heart failure in the world's population (about 19-55%), and is commonly associated with a high rate of hospitalization (almost 70-80%) and with increased mortality (40-50% in a 5-year timeframe). The elderly are more often affected, with higher rates of hospitalizations than young people, and currently almost 70% of the population aged 65 years old has HFpEF. An increase in cardiomyocyte stiffness, thus resulting in diastolic dysfunction, increased filling pressures and heart failure with preserved ejection fraction are characteristics features of the disease. In addition, among the various causes of HFpEF, cardiac amyloidosis (CA) can provoke diastolic dysfunction and increased wall stiffness directly from intercellular deposition of insoluble proteic substances and their toxic activity. Totally, almost 30 different proteins are able to form deposits, but the most frequently involved are transthyretin and misfolded monoclonal immunoglobulin light chains, which bring to two clinical conditions called transthyretin amyloidosis (ATTR) and light-chain amyloidosis (AL). Although there has been increasing attention on ATTR-CA in recent years, the actual prevalence remains underestimated, especially in people of advanced age, as well as its real impact as a cause of HFpEF, and only data derived from autoptic exams are currently available. Moreover, CA itself often mimics HFpEF, and some conflicting data on the use of predictive scores are described in the literature. The close relationship between HFpEF and CA, especially in older population and the main pathophysiological mechanisms which bond these two conditions are described in this focused review. The need to screen red flags for ATTR-CA in elderly patients with HFpEF is urgently advised, because a prompt recognition of the disease can optimize the approach to the disease with an early therapeutic, life-saving choice.

The Influence of Age and Exercise Training Status on Left Ventricular Systolic Twist Mechanics in Healthy Males-An Exploratory Study

Age-related differences in twist may be mitigated with exercise training, although this remains inconclusive. Moreover, temporal left ventricular (LV) systolic twist mechanics, including early-systolic (twistearly), and beyond peak twist (twistpeak) alone, have not been considered. Therefore, further insights are required to ascertain the influence of age and training status on twist mechanics across systole. Forty males were included and allocated into 1 of 4 groups based on age and training status: young recreationally active (YRA, n = 9; 28 ± 5 years), old recreationally active (ORA, n = 10; 68 ± 6 years), young trained (YT, n = 10; 27 ± 6 years), and old trained (OT, n = 11, 64 ± 4 years) groups. Two-dimensional speckle-tracking echocardiography was performed to determine LV twist mechanics, including twistearly, twistpeak, and total twist (twisttotal), by considering the nadir on the twist time-curve during early systole. Twisttotal was calculated by subtracting twistearly from their peak values. LV twistpeak was higher in older than younger men (p = 0.036), while twistpeak was lower in the trained than recreationally-active (p = 0.004). Twistpeak is underestimated compared with twisttotal (p < 0.001), and when early-systolic mechanics were considered, to calculate twisttotal, the age effect (p = 0.186) was dampened. LV twist was higher in older than younger age, with lower twist in exercise-trained than recreationally-active males. Twistpeak is underestimated when twistearly is not considered, with novel observations demonstrating that the age effect was dampened when considering twistearly. These findings elucidated a smaller age effect when early phases of systole are considered, while lower LV systolic mechanics were observed in older aged trained than recreationally-active males.

Cardiac Aging in the Multi-Omics Era: High-Throughput Sequencing Insights

Cardiovascular diseases are a leading cause of mortality worldwide, and the risks of both developing a disease and receiving a poor prognosis increase with age. With increasing life expectancy, understanding the mechanisms underlying heart aging has become critical. Traditional techniques have supported research into finding the physiological changes and hallmarks of cardiovascular aging, including oxidative stress, disabled macroautophagy, loss of proteostasis, and epigenetic alterations, among others. The advent of high-throughput multi-omics techniques offers new perspectives on the molecular mechanisms and cellular processes in the heart, guiding the development of therapeutic targets. This review explores the contributions and characteristics of these high-throughput techniques to unraveling heart aging. We discuss how different high-throughput omics approaches, both alone and in combination, produce robust and exciting new findings and outline future directions and prospects in studying heart aging in this new era.

Characterizing age-related changes in intact mitochondrial proteoforms in murine hearts using quantitative top-down proteomics

BACKGROUND

Cardiovascular diseases (CVDs) are the leading cause of death worldwide, and the prevalence of CVDs increases markedly with age. Due to the high energetic demand, the heart is highly sensitive to mitochondrial dysfunction. The complexity of the cardiac mitochondrial proteome hinders the development of effective strategies that target mitochondrial dysfunction in CVDs. Mammalian mitochondria are composed of over 1000 proteins, most of which can undergo post-translational modifications (PTMs). Top-down proteomics is a powerful technique for characterizing and quantifying proteoform sequence variations and PTMs. However, there are still knowledge gaps in the study of age-related mitochondrial proteoform changes using this technique. In this study, we used top-down proteomics to identify intact mitochondrial proteoforms in young and old hearts and determined changes in protein abundance and PTMs in cardiac aging.

METHODS

Intact mitochondria were isolated from the hearts of young (4-month-old) and old (24-25-month-old) mice. The mitochondria were lysed, and mitochondrial lysates were subjected to denaturation, reduction, and alkylation. For quantitative top-down analysis, there were 12 runs in total arising from 3 biological replicates in two conditions, with technical duplicates for each sample. The collected top-down datasets were deconvoluted and quantified, and then the proteoforms were identified.

RESULTS

From a total of 12 LC-MS/MS runs, we identified 134 unique mitochondrial proteins in the different sub-mitochondrial compartments (OMM, IMS, IMM, matrix). 823 unique proteoforms in different mass ranges were identified. Compared to cardiac mitochondria of young mice, 7 proteoforms exhibited increased abundance and 13 proteoforms exhibited decreased abundance in cardiac mitochondria of old mice. Our analysis also detected PTMs of mitochondrial proteoforms, including N-terminal acetylation, lysine succinylation, lysine acetylation, oxidation, and phosphorylation. Data are available via ProteomeXchange with the identifier PXD051505.

CONCLUSION

By combining mitochondrial protein enrichment using mitochondrial fractionation with quantitative top-down analysis using ultrahigh-pressure liquid chromatography (UPLC)-MS and label-free quantitation, we successfully identified and quantified intact proteoforms in the complex mitochondrial proteome. Using this approach, we detected age-related changes in abundance and PTMs of mitochondrial proteoforms in the heart.

Mitigating the effects of time in the heart and liver: the variable effects of short- and long-term caloric restriction

Caloric restriction (CR) is known for its anti-aging benefits, partly due to reduced oxidative stress and enhanced antioxidant defense. However, CR outcomes vary based on its intensity, timing, and duration. This study explored CR's effects on antioxidant activity in the heart and liver of male Wistar rats during aging. We investigated two CR paradigms: long-term CR (LTCR), started early in life, and short-term CR (STCR), initiated in middle or old age for 3 months. Contrary to previous findings of short-term CR deleterious effects of on the nervous system, our results revealed increased levels of key antioxidants after STCR. More specifically, we found an increase in GSH-Px and GSH under STCR that was particularly pronounced in the liver, while an increase in CAT and GR activities was observed in the heart of the STCR groups. Catalase was characterized as an enzyme particularly responsive to CR, as its activity was also increased in both the liver and heart after long-term caloric restriction. Our results highlight a significant tissue-specific response to CR and contribute to our understanding of the dynamic effects of CR, which in turn has implications for refining its therapeutic potential in combating age-related decline.

BioAgeNet: An Age-Informed Convolutional Autoencoder for ECG Clustering Indicating Health

Biological Age (BA) indicates the authentic ageing progression of an individual in relation to their quality of life. The noninvasive identification of BA is crucial in predicting longevity and early age-related diseases and enabling personalized healthcare. Potential biomarkers of BA are vague and need attention. The ageing process stands out as a prominent risk factor for cardiovascular diseases. Consequently, an Electrocardiogram (ECG), the most popular and easily accessible signal, is explored to analyze the effect of age. Numerous studies have delved into supervised deep-learning approaches for ECG analysis, particularly in predicting age. These studies rely on regression-based methods and necessitate additional analysis for extracting health-related insights, such as the correlation of error between Chronological Age and AI-predicted Age with mortality. Moreover, as the shortage of cardiologists' annotated data is apparent, we propose an Age-Informed Convolutional Autoencoder that clusters ECG deep features associated with age to assess the quality of life possessed at the current age. We also proposed a three-step training strategy combining model training and deep ECG features clustering with a controlled initialization. We find that a combination of age and ECG reveals the heart's BA and is a contributing biomarker for estimating the overall BA of the body. This approach marks substantial progress in analyzing age-related impacts on ECG. It provides new perspectives on different cardiovascular disorders and can potentially transform personalized healthcare in the future.

Cardiogeriatrics: the current state of the art

It is estimated that by 2050, 17% of the world's population will be greater than 85 years old, which, combined with cardiovascular disease (CVD) being the leading cause of death and disability, sets an unprecedented burden on our health and care systems. This perfect storm will be accompanied by a rise in the prevalence of CVD due to increased survival of patients with pre-existing CVD and the incidence of CVD that is associated with the process of ageing. In this review, we will focus on the diagnosis and management of common CVD conditions in old age, namely: heart failure (HF), coronary artery disease (CAD), atrial fibrillation (AF) and valvular heart disease (VHD). Despite limited evidence, clinical guidelines are increasingly considering the complexity of management of these conditions in the older person, which often coexist, for example, AF and HF or CAD and VHD. Furthermore, they, in turn, need specific consideration in the context of comorbidities, polypharmacy, frailty and impaired cognition found in this age group. Hence, the emerging role of the geriatric cardiologist is therefore vital in performing comprehensive geriatric assessment, attending multidisciplinary team meetings and ultimately considering the patient and the sum of their diseases in their totality. There have been recent advances in CVD management but how we apply these to deliver integrated care to the elderly population is key. This review article aims to bring together emerging studies and guidelines on assessment and management of CVD in the elderly, summarising latest definitions, diagnostics, therapeutics and future challenges.

Role of mitochondrial potassium channels in ageing

Ageing is described as an inevitable decline in body functions over time and an increase in susceptibility to age-related diseases. Therefore, the increase of life expectancy is also viewed as a condition in which many elderly will develop age-related diseases and disabilities, such as cardiovascular, metabolic, neurological and oncological ones. Currently, several recognized cellular hallmarks of senescence are taken in consideration to evaluate the level of biological ageing and are the topic to plan preventive/curative anti-ageing interventions, including genomic instability, epigenetic alterations, and mitochondrial dysfunction. In this scenario, alterations in the function/expression of mitochondrial ion channels have been found in ageing and associated to an impairment of calcium cycling and a reduced mitochondrial membrane potential. Although several ion channels have been described at mitochondrial level, undoubtedly the mitochondrial potassium (mitoK) channels are the most investigated. Therefore, this review summarized the evidence that sheds to light a correlation between age-related diseases and alteration of mitoK channels, focusing the attention of the main age-related diseases, i.e. cardiovascular, neurological and oncological ones.

The Senescent Heart-"Age Doth Wither Its Infinite Variety"

Cardiovascular diseases are a leading cause of morbidity and mortality world-wide. While many factors like smoking, hypertension, diabetes, dyslipidaemia, a sedentary lifestyle, and genetic factors can predispose to cardiovascular diseases, the natural process of aging is by itself a major determinant of the risk. Cardiac aging is marked by a conglomerate of cellular and molecular changes, exacerbated by age-driven decline in cardiac regeneration capacity. Although the phenotypes of cardiac aging are well characterised, the underlying molecular mechanisms are far less explored. Recent advances unequivocally link cardiovascular aging to the dysregulation of critical signalling pathways in cardiac fibroblasts, which compromises the critical role of these cells in maintaining the structural and functional integrity of the myocardium. Clearly, the identification of cardiac fibroblast-specific factors and mechanisms that regulate cardiac fibroblast function in the senescent myocardium is of immense importance. In this regard, recent studies show that Discoidin domain receptor 2 (DDR2), a collagen-activated receptor tyrosine kinase predominantly located in cardiac fibroblasts, has an obligate role in cardiac fibroblast function and cardiovascular fibrosis. Incisive studies on the molecular basis of cardiovascular aging and dysregulated fibroblast function in the senescent heart would pave the way for effective strategies to mitigate cardiovascular diseases in a rapidly growing elderly population.

Atrial myopathy

This paper delves into the progressive concept of atrial myopathy, shedding light on its development and its impact on atrial characteristics. It extensively explores the intricate connections between atrial myopathy, atrial fibrillation (AF), and strokes. Researchers have sought additional contributors to AF-related strokes due to the absence of a clear timing correlation between paroxysmal AF episodes and strokes in patients with cardiac implantable electronic devices. Through various animal models and human investigations, a close interrelation among aging, inflammation, oxidative stress, and stretching mechanisms has been identified. These mechanisms contribute to fibrosis, alterations in electrical properties, autonomic remodeling, and a heightened pro-thrombotic state. These interconnected factors establish a detrimental cycle, exacerbating atrial myopathy and elevating the risk of sustained AF and strokes. By emphasizing the significance of atrial myopathy and the risk of strokes that are distinct from AF, the paper also discusses methods for identifying patients with atrial myopathy. Moreover, it proposes an approach to incorporate the concept of atrial myopathy into clinical practice to guide anticoagulation decisions in individuals with AF.

Characterizing Age-related Changes in Intact Mitochondrial Proteoforms in Murine Hearts using Quantitative Top-Down Proteomics

Cardiovascular diseases (CVDs) are the leading cause of death worldwide, and the prevalence of CVDs increases markedly with age. Due to the high energetic demand, the heart is highly sensitive to mitochondrial dysfunction. The complexity of the cardiac mitochondrial proteome hinders the development of effective strategies that target mitochondrial dysfunction in CVDs. Mammalian mitochondria are composed of over 1000 proteins, most of which can undergo post-translational protein modifications (PTMs). Top-down proteomics is a powerful technique for characterizing and quantifying all protein sequence variations and PTMs. However, there are still knowledge gaps in the study of age-related mitochondrial proteoform changes using this technique. In this study, we used top-down proteomics to identify intact mitochondrial proteoforms in young and old hearts and determined changes in protein abundance and PTMs in cardiac aging.

METHODS

Intact mitochondria were isolated from the hearts of young (4-month-old) and old (24-25-month-old) mice. The mitochondria were lysed, and mitochondrial lysates were subjected to denaturation, reduction, and alkylation. For quantitative top-down analysis, there were 12 runs in total arising from 3 biological replicates in two conditions, with technical duplicates for each sample. The collected top-down datasets were deconvoluted and quantified, and then the proteoforms were identified.

RESULTS

From a total of 12 LC-MS/MS runs, we identified 134 unique mitochondrial proteins in the different sub-mitochondrial compartments (OMM, IMS, IMM, matrix). 823 unique proteoforms in different mass ranges were identified. Compared to cardiac mitochondria of young mice, 7 proteoforms exhibited increased abundance and 13 proteoforms exhibited decreased abundance in cardiac mitochondria of old mice. Our analysis also detected PTMs of mitochondrial proteoforms, including N-terminal acetylation, lysine succinylation, lysine acetylation, oxidation, and phosphorylation.

CONCLUSION

By combining mitochondrial protein enrichment using mitochondrial fractionation with quantitative top-down analysis using ultrahigh-pressure liquid chromatography (UPLC)-MS and label-free quantitation, we successfully identified and quantified intact proteoforms in the complex mitochondrial proteome. Using this approach, we detected age-related changes in abundance and PTMs of mitochondrial proteoforms in the heart.

Heart Failure with Preserved Ejection Fraction: The Pathophysiological Mechanisms behind the Clinical Phenotypes and the Therapeutic Approach

Heart failure (HF) with preserved ejection fraction (HFpEF) is an increasingly frequent form and is estimated to be the dominant form of HF. On the other hand, HFpEF is a syndrome with systemic involvement, and it is characterized by multiple cardiac and extracardiac pathophysiological alterations. The increasing prevalence is currently reaching epidemic levels, thereby making HFpEF one of the greatest challenges facing cardiovascular medicine today. Compared to HF with reduced ejection fraction (HFrEF), the medical attitude in the case of HFpEF was a relaxed one towards the disease, despite the fact that it is much more complex, with many problems related to the identification of physiopathogenetic mechanisms and optimal methods of treatment. The current medical challenge is to develop effective therapeutic strategies, because patients suffering from HFpEF have symptoms and quality of life comparable to those with reduced ejection fraction, but the specific medication for HFrEF is ineffective in this situation; for this, we must first understand the pathological mechanisms in detail and correlate them with the clinical presentation. Another important aspect of HFpEF is the diversity of patients that can be identified under the umbrella of this syndrome. Thus, before being able to test and develop effective therapies, we must succeed in grouping patients into several categories, called phenotypes, depending on the pathological pathways and clinical features. This narrative review critiques issues related to the definition, etiology, clinical features, and pathophysiology of HFpEF. We tried to describe in as much detail as possible the clinical and biological phenotypes recognized in the literature in order to better understand the current therapeutic approach and the reason for the limited effectiveness. We have also highlighted possible pathological pathways that can be targeted by the latest research in this field.

Heart failure and economic impact: an analysis in real clinical practice in Italy

Introduction: Heart failure (HF) affects 1% of subjects aged 45-55 and over 10% of subjects aged ≥ 80 and in Italy represents the third leading cause of hospitalization. Objective: To analyse the clinical and economic burden of HF in the Italian real clinical practice. Methods: A retrospective analysis was conducted on the administrative databases of healthcare institutions for 4.2 million health-assisted residents. Between January 2012 and March 2021, patients with a hospital discharge diagnosis for HF were included. Among healthcare utilization and costs, treatments, hospitalizations, and specialist services were evaluated. The HF group was compared with a population without HF (no-HF) similar for age, sex distribution, and cardiovascular risk factors. Results: The same number of patients with (N = 74,085) and without HF (N = 74,085) was included. A profile of cardiovascular comorbidities emerged in the HF group, mainly hypertension (88.6%), cardiovascular disease (61.3%) and diabetes (32.1%). Hospitalizations from any cause were 635.6 vs 429.8/1,000 person-year in the HF vs no-HF group. At one-year follow-up, all-cause mortality was 24.9% in HF patients and 8.4% in no-HF. Resource utilization/patient was respectively 26.8 ± 15.9 vs 17.1 ± 12.5 for medications, 0.8 ± 1.2 vs 0.3 ± 0.8 for hospitalizations, and 9.4 ± 12.6 vs 6.5 ± 9.8 for specialist services. This resource utilization resulted in significantly higher total healthcare costs in the HF group vs no-HF group (€ 5,910 vs € 3,574, p < 0.001), mainly related to hospitalizations (€ 3,702 vs € 1,958). Conclusions: HF patients show a significantly higher clinical and economic burden than no-HF, with total healthcare costs being about 1.7 times the costs of the no-HF group. Keywords: Cardiovascular comorbidities, Healthcare costs, Heart failure, Hospitalizations

Neutrophil peptidylarginine deiminase 4 is essential for detrimental age-related cardiac remodelling and dysfunction in mice

Mice fully deficient in peptidylarginine deiminase 4 (PAD4) enzyme have preserved cardiac function and reduced collagen deposition during ageing. The cellular source of PAD4 is hypothesized to be neutrophils, likely due to PAD4's involvement in neutrophil extracellular trap release. We investigated haematopoietic PAD4 impact on myocardial remodelling and systemic inflammation in cardiac ageing by generating mice with Padi4 deletion in circulating neutrophils under the MRP8 promoter (Ne-PAD4-/-), and ageing them for 2 years together with littermate controls (PAD4fl/fl). Ne-PAD4-/- mice showed protection against age-induced fibrosis, seen by reduced cardiac collagen deposition. Echocardiography analysis of structural and functional parameters also demonstrated preservation of both systolic and diastolic function with MRP8-driven PAD4 deletion. Furthermore, cardiac gene expression and plasma cytokine levels were evaluated. Cardiac genes and plasma cytokines involved in neutrophil recruitment were downregulated in aged Ne-PAD4-/- animals compared to PAD4fl/fl controls, including decreased levels of C-X-C ligand 1 (CXCL1). Our data confirm PAD4 involvement from circulating neutrophils in detrimental cardiac remodelling, leading to cardiac dysfunction with old age. Deletion of PAD4 in MRP8-expressing cells impacts the CXCL1-CXCR2 axis, known to be involved in heart failure development. This supports the future use of PAD4 inhibitors in cardiovascular disease. This article is part of the Theo Murphy meeting issue 'The virtues and vices of protein citrullination'.

Doxorubicin-Induced Cardiac Senescence Is Alleviated Following Treatment with Combined Polyphenols and Micronutrients through Enhancement in Mitophagy

Oxidative stress and impaired mitophagy are the hallmarks of cardiomyocyte senescence. Specifically, a decrease in mitophagic flux leads to the accumulation of damaged mitochondria and the development of senescence through increased ROS and other mediators. In this study, we describe the preventive role of A5+, a mix of polyphenols and other micronutrients, in doxorubicin (DOXO)-induced senescence of H9C2 cells. Specifically, H9C2 cells exposed to DOXO showed an increase in the protein expression proteins of senescence-associated genes, p21 and p16, and a decrease in the telomere binding factors TRF1 and TRF2, indicative of senescence induction. Nevertheless, A5+ pre-treatment attenuated the senescent-like cell phenotype, as evidenced by inhibition of all senescent markers and a decrease in SA-β-gal staining in DOXO-treated H9C2 cells. Importantly, A5+ restored the LC3 II/LC3 I ratio, Parkin and BNIP3 expression, therefore rescuing mitophagy, and decreased ROS production. Further, A5+ pre-treatment determined a ripolarization of the mitochondrial membrane and improved basal respiration. A5+-mediated protective effects might be related to its ability to activate mitochondrial SIRT3 in synergy with other micronutrients, but in contrast with SIRT4 activation. Accordingly, SIRT4 knockdown in H9C2 cells further increased MnSOD activity, enhanced mitophagy, and reduced ROS generation following A5+ pre-treatment and DOXO exposure compared to WT cells. Indeed, we demonstrated that A5+ protects H9C2 cells from DOXO-induced senescence, establishing a new specific role for A5+ in controlling mitochondrial quality control by restoring SIRT3 activity and mitophagy, which provided a molecular basis for the development of therapeutic strategies against cardiomyocyte senescence.

Apoptosis and long non-coding RNAs: Focus on their roles in Heart diseases

Heart disease is one of the principal death reasons around the world and there is a growing requirement to discover novel healing targets that have the potential to avert or manage these illnesses. On the other hand, apoptosis is a strongly controlled, cell removal procedure that has a crucial part in numerous cardiac problems, such as reperfusion injury, MI (myocardial infarction), consecutive heart failure, and inflammation of myocardium. Completely comprehending the managing procedures of cell death signaling is critical as it is the primary factor that influences patient mortality and morbidity, owing to cardiomyocyte damage. Indeed, the prevention of heart cell death appears to be a viable treatment approach for heart illnesses. According to current researches, a number of long non-coding RNAs cause the heart cells death via different methods that are embroiled in controlling the activity of transcription elements, the pathways that signals transmission within cells, small miRNAs, and the constancy of proteins. When there is too much cell death in the heart, it can cause problems like reduced blood flow, heart damage after restoring blood flow, heart disease in diabetics, and changes in the heart after reduced blood flow. Therefore, studying how lncRNAs control apoptosis could help us find new treatments for heart diseases. In this review, we present recent discoveries about how lncRNAs are involved in causing cell death in different cardiovascular diseases.

Circulating Total Extracellular Vesicles Cargo Are Associated with Age-Related Oxidative Stress and Susceptibility to Cardiovascular Diseases: Exploratory Results from Microarray Data

Aging is a risk factor for many non-communicable diseases such as cardiovascular and neurodegenerative diseases. Extracellular vesicles and particles (EVP) carry microRNAs that may play a role in age-related diseases and may induce oxidative stress. We hypothesized that aging could impact EVP miRNA and impair redox homeostasis, contributing to chronic age-related diseases. Our aims were to investigate the microRNA profiles of circulating total EVPs from aged and young adult animals and to evaluate the pro- and antioxidant machinery in circulating total EVPs. Plasma from 3- and 21-month-old male Wistar rats were collected, and total EVPs were isolated. MicroRNA isolation and microarray expression analysis were performed on EVPs to determine the predicted regulation of targeted mRNAs. Thirty-one mature microRNAs in circulating EVPs were impacted by age and were predicted to target molecules in canonical pathways directly related to cardiovascular diseases and oxidative status. Circulating total EVPs from aged rats had significantly higher NADPH oxidase levels and myeloperoxidase activity, whereas catalase activity was significantly reduced in EVPs from aged animals. Our data shows that circulating total EVP cargo-specifically microRNAs and oxidative enzymes-are involved in redox imbalance in the aging process and can potentially drive cardiovascular aging and, consequently, cardiac disease.

SIRT2 counteracts primate cardiac aging via deacetylation of STAT3 that silences CDKN2B

Aging is a major risk factor contributing to pathophysiological changes in the heart, yet its intrinsic mechanisms have been largely unexplored in primates. In this study, we investigated the hypertrophic and senescence phenotypes in the hearts of aged cynomolgus monkeys as well as the transcriptomic and proteomic landscapes of young and aged primate hearts. SIRT2 was identified as a key protein decreased in aged monkey hearts, and engineered SIRT2 deficiency in human pluripotent stem cell-derived cardiomyocytes recapitulated key senescence features of primate heart aging. Further investigations revealed that loss of SIRT2 in human cardiomyocytes led to the hyperacetylation of STAT3, which transcriptionally activated CDKN2B and, in turn, triggered cardiomyocyte degeneration. Intra-myocardial injection of lentiviruses expressing SIRT2 ameliorated age-related cardiac dysfunction in mice. Taken together, our study provides valuable resources for decoding primate cardiac aging and identifies the SIRT2-STAT3-CDKN2B regulatory axis as a potential therapeutic target against human cardiac aging and aging-related cardiovascular diseases.

Environmental and genetic predictors of human cardiovascular ageing

Cardiovascular ageing is a process that begins early in life and leads to a progressive change in structure and decline in function due to accumulated damage across diverse cell types, tissues and organs contributing to multi-morbidity. Damaging biophysical, metabolic and immunological factors exceed endogenous repair mechanisms resulting in a pro-fibrotic state, cellular senescence and end-organ damage, however the genetic architecture of cardiovascular ageing is not known. Here we use machine learning approaches to quantify cardiovascular age from image-derived traits of vascular function, cardiac motion and myocardial fibrosis, as well as conduction traits from electrocardiograms, in 39,559 participants of UK Biobank. Cardiovascular ageing is found to be significantly associated with common or rare variants in genes regulating sarcomere homeostasis, myocardial immunomodulation, and tissue responses to biophysical stress. Ageing is accelerated by cardiometabolic risk factors and we also identify prescribed medications that are potential modifiers of ageing. Through large-scale modelling of ageing across multiple traits our results reveal insights into the mechanisms driving premature cardiovascular ageing and reveal potential molecular targets to attenuate age-related processes.

Late Effects of Chronic Low Dose Rate Total Body Irradiation on the Heart Proteome of ApoE-/- Mice Resemble Premature Cardiac Ageing

Recent epidemiologic studies support an association between chronic low-dose radiation exposure and the development of cardiovascular disease (CVD). The molecular mechanisms underlying the adverse effect of chronic low dose exposure are not fully understood. To address this issue, we have investigated changes in the heart proteome of ApoE deficient (ApoE^-/-) C57Bl/6 female mice chronically irradiated for 300 days at a very low dose rate (1 mGy/day) or at a low dose rate (20 mGy/day), resulting in cumulative whole-body doses of 0.3 Gy or 6.0 Gy, respectively. The heart proteomes were compared to those of age-matched sham-irradiated ApoE^-/- mice using label-free quantitative proteomics. Radiation-induced proteome changes were further validated using immunoblotting, enzyme activity assays, immunohistochemistry or targeted transcriptomics. The analyses showed persistent alterations in the cardiac proteome at both dose rates; however, the effect was more pronounced following higher dose rates. The altered proteins were involved in cardiac energy metabolism, ECM remodelling, oxidative stress, and ageing signalling pathways. The changes in PPARα, SIRT, AMPK, and mTOR signalling pathways were found at both dose rates and in a dose-dependent manner, whereas more changes in glycolysis and ECM remodelling were detected at the lower dose rate. These data provide strong evidence for the possible risk of cardiac injury following chronic low dose irradiation and show that several affected pathways following chronic irradiation overlap with those of ageing-associated heart pathology.

Late-life Rapamycin Treatment Enhances Cardiomyocyte Relaxation Kinetics and Reduces Myocardial Stiffness

Diastolic dysfunction is a key feature of the aging heart. We have shown that late-life treatment with mTOR inhibitor, rapamycin, reverses age-related diastolic dysfunction in mice but the molecular mechanisms of the reversal remain unclear. To dissect the mechanisms by which rapamycin improves diastolic function in old mice, we examined the effects of rapamycin treatment at the levels of single cardiomyocyte, myofibril and multicellular cardiac muscle. Compared to young cardiomyocytes, isolated cardiomyocytes from old control mice exhibited prolonged time to 90% relaxation (RT 90 ) and time to 90% Ca 2+ transient decay (DT 90 ), indicating slower relaxation kinetics and calcium reuptake with age. Late-life rapamycin treatment for 10 weeks completely normalized RT 90 and partially normalized DT 90 , suggesting improved Ca 2+ handling contributes partially to the rapamycin-induced improved cardiomyocyte relaxation. In addition, rapamycin treatment in old mice enhanced the kinetics of sarcomere shortening and Ca 2+ transient increase in old control cardiomyocytes. Myofibrils from old rapamycin-treated mice displayed increased rate of the fast, exponential decay phase of relaxation compared to old controls. The improved myofibrillar kinetics were accompanied by an increase in MyBP-C phosphorylation at S282 following rapamycin treatment. We also showed that late-life rapamycin treatment normalized the age-related increase in passive stiffness of demembranated cardiac trabeculae through a mechanism independent of titin isoform shift. In summary, our results showed that rapamycin treatment normalizes the age-related impairments in cardiomyocyte relaxation, which works conjointly with reduced myocardial stiffness to reverse age-related diastolic dysfunction.

Accelerated ageing and coronary microvascular dysfunction in chronic heart failure in Tgαq*44 mice

Age represents a major risk factor in heart failure (HF). However, the mechanisms linking ageing and HF are not clear. We aimed to identify the functional, morphological and transcriptomic changes that could be attributed to cardiac ageing in a model of slowly progressing HF in Tgαq*44 mice in reference to the cardiac ageing process in FVB mice. In FVB mice, ageing resulted in the impairment of diastolic cardiac function and in basal coronary flow (CF), perivascular and interstitial fibrosis without changes in the cardiac activity of angiotensin-converting enzyme (ACE) or aldosterone plasma concentration. In Tgαq*44 mice, HF progression was featured by the impairment of systolic and diastolic cardiac function and in basal CF that was associated with a distinct rearrangement of the capillary architecture, pronounced perivascular and interstitial fibrosis, progressive activation of cardiac ACE and systemic angiotensin-aldosterone-dependent pathways. Interestingly, cardiac ageing genes and processes were represented in Tgαq*44 mice not only in late but also in early phases of HF, as evidenced by cardiac transcriptome analysis. Thirty-four genes and 8 biological processes, identified as being ageing related, occurred early and persisted along HF progression in Tgαq*44 mice and were mostly associated with extracellular matrix remodelling and fibrosis compatible with perivascular fibrosis resulting in coronary microvascular dysfunction (CMD) in Tgαq*44 mice. In conclusion, accelerated and persistent cardiac ageing contributes to the pathophysiology of chronic HF in Tgαq*44 mice. In particular, prominent perivascular fibrosis of microcirculation resulting in CMD represents an accelerated cardiac ageing phenotype that requires targeted treatment in chronic HF.

Klotho protects against aged myocardial cells by attenuating ferroptosis

Klotho (KL) is a renal protein with aging-suppression properties that mediates its regulatory effect during cardiac fibroblast aging. However, to determine whether KL can protect aged myocardial cells by attenuating ferroptosis, this study aimed to investigate the protective effect of KL on aged cells and to explore its potential mechanism. Cell injury of H9C2 cells was induced with D-galactose (D-gal) and treated with KL in vitro. This study demonstrated that D-gal induces aging in H9C2 cells. D-gal treatment increased β-GAL(β-galactosidase) activity, decreased cell viability, enhanced oxidative stress, reduced mitochondrial cristae, and decreased the expression of solute carrier family 7 member 11 (SLC7A11), glutathione peroxidase-4 (GPx4), and P53, which are primary regulators of ferroptosis. The results showed that KL can eliminate D-gal-induced aging in H9C2 cells, likely due to its ability to increase the expression of the ferroptosis-associated proteins SLC7A11 and GPx4. Moreover, pifithrin-α, a P53-specific inhibitor, attenuated the expression of SLC7A11 and GPx4. These results suggest that KL may be involved in D-gal-induced H9C2 cellular aging during ferroptosis, mainly through the P53/SLC7A11/GPx4 signaling pathway.

Clinical profiling of end-stage heart failure with preserved ejection fraction: The National Readmission Database

BACKGROUND

End-stage (Stage D) heart failure with preserved ejection fraction (HFpEF) is a poorly characterized syndrome that has heterogeneous underlying pathophysiology. A better characterization of the various clinical profiles of Stage D HFpEF is needed.

METHOD

1066 patients with Stage D HFpEF were selected from National Readmission Database. A Bayesian clustering algorithm based on a Dirichlet process mixture model was implemented. Cox proportional hazard regression model was used to relate the risk of in-hospital mortality with each identified clinical cluster.

RESULT

4 distinct clinical clusters were recognized. Group 1 had a higher prevalence of obesity (84.5%) and sleep disorders (62.0%). Group 2 had a higher prevalence of diabetes mellitus (92%), chronic kidney disease (98.3%), anemia (72.6%), and coronary artery disease (59.0%). Group 3 had a higher prevalence of advanced age (82.1%), hypothyroidism (28.9%), dementia (17.0%), atrial fibrillation (63.8%) and valvular disease (30.5%) and Group 4 had a higher prevalence of liver disease (44.5%), right-sided HF (20.2%) and amyloidosis (4.5%). During 2019, 193 (18.1%) in-hospital mortality events occurred. Considering Group 1 (with mortality rate of 4.1%) as a reference, the hazard ratio of in-hospital mortality was 5.4 [95% confidence interval (CI): 2.2-13.6] for Group 2, 6.4 (95% CI: 2.6-15.8) for Group 3 and 9.1 (95% CI: 3.5-23.8) for Group 4.

CONCLUSION

End-stage HFpEF presents with different clinical profiles with varied upstream causes. This may help provide evidence toward the development of targeted therapies.

The loss of cardiac SIRT3 decreases metabolic flexibility and proteostasis in an age-dependent manner

SIRT3 is a longevity factor that acts as the primary deacetylase in mitochondria. Although ubiquitously expressed, previous global SIRT3 knockout studies have shown primarily a cardiac-specific phenotype. Here, we sought to determine how specifically knocking out SIRT3 in cardiomyocytes (SIRTcKO mice) temporally affects cardiac function and metabolism. Mice displayed an age-dependent increase in cardiac pathology, with 10-month-old mice exhibiting significant loss of systolic function, hypertrophy, and fibrosis. While mitochondrial function was maintained at 10 months, proteomics and metabolic phenotyping indicated SIRT3 hearts had increased reliance on glucose as an energy substrate. Additionally, there was a significant increase in branched-chain amino acids in SIRT3cKO hearts without concurrent increases in mTOR activity. Heavy water labeling experiments demonstrated that, by 3 months of age, there was an increase in protein synthesis that promoted hypertrophic growth with a potential loss of proteostasis in SIRT3cKO hearts. Cumulatively, these data show that the cardiomyocyte-specific loss of SIRT3 results in severe pathology with an accelerated aging phenotype.

Mitochondrial miRNA as epigenomic signatures: Visualizing aging-associated heart diseases through a new lens

Aging bears many hard knocks, but heart disorders earn a particular allusion, being the most widespread. Cardiovascular diseases (CVDs) are becoming the biggest concern to mankind due to sundry health conditions directly or indirectly related to heart-linked abnormalities. Scientists know that mitochondria play a critical role in the pathophysiology of cardiac diseases. Both environment and genetics play an essential role in modulating and controlling mitochondrial functions. Even a minor abnormality may prove detrimental to heart function. Advanced age combined with an unhealthy lifestyle can cause most cardiomyocytes to be replaced by fibrotic tissue which upsets the conducting system and leads to arrhythmias. An aging heart encounters far more heart-associated comorbidities than a young heart. Many state-of-the-art technologies and procedures are already being used to prevent and treat heart attacks worldwide. However, it remains a mystery when this heart bomb would explode because it lacks an alarm. This calls for a novel and effective strategy for timely diagnosis and a sure-fire treatment. This review article provides a comprehensive overture of prospective potentials of mitochondrial miRNAs that predict complicated and interconnected pathways concerning heart ailments and signature compilations of relevant miRNAs as biomarkers to plot the role of miRNAs in epigenomics. This article suggests that analysis of DNA methylation patterns in age-associated heart diseases may determine age-impelled biomarkers of heart disease.

Effect of polygenic risk for schizophrenia on cardiac structure and function: a UK Biobank observational study

BACKGROUND

Cardiovascular disease is a major cause of excess mortality in people with schizophrenia. Several factors are responsible, including lifestyle and metabolic effects of antipsychotics. However, variations in cardiac structure and function are seen in people with schizophrenia in the absence of cardiovascular disease risk factors and after accounting for lifestyle and medication. Therefore, we aimed to explore whether shared genetic causes contribute to these cardiac variations.

METHODS

For this observational study, we used data from the UK Biobank and included White British or Irish individuals without diagnosed schizophrenia with variable polygenic risk scores for the condition. To test the association between polygenic risk score for schizophrenia and cardiac phenotype, we used principal component analysis and regression. Robust regression was then used to explore the association between the polygenic risk score for schizophrenia and individual cardiac phenotypes. We repeated analyses with fibro-inflammatory pathway-specific polygenic risk scores for schizophrenia. Last, we investigated genome-wide sharing of common variants between schizophrenia and cardiac phenotypes using linkage disequilibrium score regression. The primary outcome was principal component regression.

FINDINGS

Of 33 353 individuals recruited, 32 279 participants had complete cardiac MRI data and were included in the analysis, of whom 16 625 (51·5%) were female and 15 654 (48·5%) were male. 1074 participants were excluded on the basis of incomplete cardiac MRI data (for all phenotypes). A model regressing polygenic risk scores for schizophrenia onto the first five cardiac principal components of the principal components analysis was significant (F=5·09; p=0·00012). Principal component 1 captured a pattern of increased cardiac volumes, increased absolute peak diastolic strain rates, and reduced ejection fractions; polygenic risk scores for schizophrenia and principal component 1 were negatively associated (β=-0·01 [SE 0·003]; p=0·017). Similar to the principal component analysis results, for individual cardiac phenotypes, we observed negative associations between polygenic risk scores for schizophrenia and indexed right ventricular end-systolic volume (β=-0·14 [0·04]; p=0·0013, pFDR=0·015), indexed right ventricular end-diastolic volume (β=-0·17 [0·08]); p=0·025; pFDR=0·082), and absolute longitudinal peak diastolic strain rates (β=-0·01 [0·003]; p=0·0024, pFDR=0·015), and a positive association between polygenic risk scores for schizophrenia and right ventricular ejection fraction (β=0·09 [0·03]; p=0·0041, pFDR=0·015). Models examining the transforming growth factor-β (TGF-β)-specific and acute inflammation-specific polygenic risk scores for schizophrenia found significant associations with the first five principal components (F=2·62, p=0·022; F=2·54, p=0·026). Using linkage disequilibrium score regression, we observed genetic overlap with schizophrenia for right ventricular end-systolic volume and right ventricular ejection fraction (p=0·0090, p=0·0077).

INTERPRETATION

High polygenic risk scores for schizophrenia are associated with decreased cardiac volumes, increased ejection fractions, and decreased absolute peak diastolic strain rates. TGF-β and inflammatory pathways might be implicated, and there is evidence of genetic overlap for some cardiac phenotypes. Reduced absolute peak diastolic strain rates indicate increased myocardial stiffness and diastolic dysfunction, which increases risk of cardiac disease. Thus, genetic risk for schizophrenia is associated with cardiac structural changes that can worsen cardiac outcomes. Further work is required to determine whether these associations are specific to schizophrenia or are also seen in other psychiatric conditions.

FUNDING

National Institute for Health Research, Maudsley Charity, Wellcome Trust, Medical Research Council, Academy of Medical Sciences, Edmond J Safra Foundation, British Heart Foundation.

A small erythropoietin derived non-hematopoietic peptide reduces cardiac inflammation, attenuates age associated declines in heart function and prolongs healthspan

Background

Aging is associated with increased levels of reactive oxygen species and inflammation that disrupt proteostasis and mitochondrial function and leads to organism-wide frailty later in life. ARA290 (cibinetide), an 11-aa non-hematopoietic peptide sequence within the cardioprotective domain of erythropoietin, mediates tissue protection by reducing inflammation and fibrosis. Age-associated cardiac inflammation is linked to structural and functional changes in the heart, including mitochondrial dysfunction, impaired proteostasis, hypertrophic cardiac remodeling, and contractile dysfunction. Can ARA290 ameliorate these age-associated cardiac changes and the severity of frailty in advanced age?

Methods

We conducted an integrated longitudinal (n = 48) and cross-sectional (n = 144) 15 months randomized controlled trial in which 18-month-old Fischer 344 x Brown Norway rats were randomly assigned to either receive chronic ARA290 treatment or saline. Serial echocardiography, tail blood pressure and body weight were evaluated repeatedly at 4-month intervals. A frailty index was calculated at the final timepoint (33 months of age). Tissues were harvested at 4-month intervals to define inflammatory markers and left ventricular tissue remodeling. Mitochondrial and myocardial cell health was assessed in isolated left ventricular myocytes. Kaplan-Meier survival curves were established. Mixed ANOVA tests and linear mixed regression analysis were employed to determine the effects of age, treatment, and age-treatment interactions.

Results

Chronic ARA290 treatment mitigated age-related increases in the cardiac non-myocyte to myocyte ratio, infiltrating leukocytes and monocytes, pro-inflammatory cytokines, total NF-κB, and p-NF-κB. Additionally, ARA290 treatment enhanced cardiomyocyte autophagy flux and reduced cellular accumulation of lipofuscin. The cardiomyocyte mitochondrial permeability transition pore response to oxidant stress was desensitized following chronic ARA290 treatment. Concurrently, ARA290 significantly blunted the age-associated elevation in blood pressure and preserved the LV ejection fraction. Finally, ARA290 preserved body weight and significantly reduced other markers of organism-wide frailty at the end of life.

Conclusion

Administration of ARA290 reduces cell and tissue inflammation, mitigates structural and functional changes within the cardiovascular system leading to amelioration of frailty and preserved healthspan.

The longevity-associated BPIFB4 gene supports cardiac function and vascularization in aging cardiomyopathy

AIMS

The aging heart naturally incurs a progressive decline in function and perfusion that available treatments cannot halt. However, some exceptional individuals maintain good health until the very late stage of their life due to favourable gene-environment interaction. We have previously shown that carriers of a longevity-associated variant (LAV) of the BPIFB4 gene enjoy prolonged health spans and lesser cardiovascular complications. Moreover, supplementation of LAV-BPIFB4 via an adeno-associated viral vector improves cardiovascular performance in limb ischemia, atherosclerosis, and diabetes models. Here, we asked if the LAV-BPIFB4 gene could address the unmet therapeutic need to delay the heart's spontaneous aging.

METHODS AND RESULTS

Immunohistological studies showed a remarkable reduction in vessel coverage by pericytes in failing hearts explanted from elderly patients. This defect was attenuated in patients carrying the homozygous LAV-BPIFB4 genotype. Moreover, pericytes isolated from older hearts showed low levels of BPIFB4, depressed pro-angiogenic activity, and loss of ribosome biogenesis. LAV-BPIFB4 supplementation restored pericyte function and pericyte-endothelial cell interactions through a mechanism involving the nucleolar protein nucleolin. Conversely, BPIFB4 silencing in normal pericytes mimed the heart failure pericytes. Finally, gene therapy with LAV-BPIFB4 prevented cardiac deterioration in middle-aged mice and rescued cardiac function and myocardial perfusion in older mice by improving microvasculature density and pericyte coverage.

CONCLUSIONS

We report the success of the LAV-BPIFB4 gene/protein in improving homeostatic processes in the heart's aging. These findings open to using LAV-BPIFB4 to reverse the decline of heart performance in older people.

Carotid Body-Mediated Chemoreflex Function in Aging and the Role of Receptor-Interacting Protein Kinase

Ventilatory impairment during aging has been linked to carotid body (CB) dysfunction. Anatomical/morphological studies evidenced CB degeneration and reductions in the number of CB chemoreceptor cells during aging. The mechanism(s) related to CB degeneration in aging remains elusive. Programmed cell death encompasses both apoptosis and necroptosis. Interestingly, necroptosis can be driven by molecular pathways related to low-grade inflammation, one hallmark of the aging process. Accordingly, we hypothesized that necrotic cell death dependent on receptor-interacting protein kinase-3 (RIPK3) may contribute, at least in part, to impair CB function during aging. Adult (3 months) and aged (24 months) wild type (WT) and RIPK3^-/- mice were used to study chemoreflex function. Aging results in significant reductions in both the hypoxic (HVR) and hypercapnic ventilatory responses (HCVR). Adult RIPK3^-/- mice showed normal HVR and HCVR compared to adult WT mice. Remarkable, aged RIPK3^-/- mice displayed no reductions in HVR nor in HCVR. Indeed, chemoreflex responses obtained in aged RIPK3^-/- KO mice were undistinguishable from the ones obtained in adult WT mice. Lastly, we found high prevalence of breathing disorders during aging and this was absent in aged RIPK3^-/- mice. Together our results support a role for RIPK3-mediated necroptosis in CB dysfunction during aging.

The Aging Heart: A Molecular and Clinical Challenge

Aging is associated with an increasing burden of morbidity, especially for cardiovascular diseases (CVDs). General cardiovascular risk factors, ischemic heart diseases, heart failure, arrhythmias, and cardiomyopathies present a significant prevalence in older people, and are characterized by peculiar clinical manifestations that have distinct features compared with the same conditions in a younger population. Remarkably, the aging heart phenotype in both healthy individuals and patients with CVD reflects modifications at the cellular level. An improvement in the knowledge of the physiological and pathological molecular mechanisms underlying cardiac aging could improve clinical management of older patients and offer new therapeutic targets.

Aging Increases Susceptibility to Develop Cardiac Hypertrophy following High Sugar Consumption

Aging and poor diet are independent risk factors for heart disease, but the impact of high-sucrose (HS) consumption in the aging heart is understudied. Aging leads to impairments in mitochondrial function that result in muscle dysfunction (e.g., cardiac remodeling and sarcopenia). We tested whether HS diet (60%kcal sucrose) would accelerate muscle dysfunction in 24-month-old male CB6F1 mice. By week 1 on HS diet, mice developed significant cardiac hypertrophy compared to age-matched chow-fed controls. The increased weight of the heart persisted throughout the 4-week treatment, while body weight and strength declined more rapidly than controls. We then tested whether HS diet could worsen cardiac dysfunction in old mice and if the mitochondrial-targeted drug, elamipretide (ELAM), could prevent the diet-induced effect. Old and young mice were treated with either ELAM or saline as a control for 2 weeks, and provided with HS diet or chow on the last week. As demonstrated in the previous experiment, old mice had age-related cardiac hypertrophy that worsened after one week on HS and was prevented by ELAM treatment, while the HS diet had no detectable effect on hypertrophy in the young mice. As expected, mitochondrial respiration and reactive oxygen species (ROS) production were altered by age, but were not significantly affected by HS diet or ELAM. Our findings highlight the vulnerability of the aged heart to HS diet that can be prevented by systemic targeting of the mitochondria with ELAM.

Metabolomic Profiling of End-Stage Heart Failure Secondary to Chronic Chagas Cardiomyopathy

Chronic Chagas cardiomyopathy (CCC) is the most frequent and severe clinical form of chronic Chagas disease, representing one of the leading causes of morbidity and mortality in Latin America, and a growing global public health problem. There is currently no approved treatment for CCC; however, omics technologies have enabled significant progress to be made in the search for new therapeutic targets. The metabolic alterations associated with pathogenic mechanisms of CCC and their relationship to cellular and immunopathogenic processes in cardiac tissue remain largely unknown. This exploratory study aimed to evaluate the potential underlying pathogenic mechanisms in the failing myocardium of patients with end-stage heart failure (ESHF) secondary to CCC by applying an untargeted metabolomic profiling approach. Cardiac tissue samples from the left ventricle of patients with ESHF of CCC etiology (n = 7) and healthy donors (n = 7) were analyzed using liquid chromatography-mass spectrometry. Metabolite profiles showed altered branched-chain amino acid and acylcarnitine levels, decreased fatty acid uptake and oxidation, increased activity of the pentose phosphate pathway, dysregulation of the TCA cycle, and alterations in critical cellular antioxidant systems. These findings suggest processes of energy deficit, alterations in substrate availability, and enhanced production of reactive oxygen species in the affected myocardium. This profile potentially contributes to the development and maintenance of a chronic inflammatory state that leads to progression and severity of CCC. Further studies involving larger sample sizes and comparisons with heart failure patients without CCC are needed to validate these results, opening an avenue to investigate new therapeutic approaches for the treatment and prevention of progression of this unique and severe cardiomyopathy.

Atrial cardiopathy and cognitive impairment

Cognitive impairment involves complex interactions between multiple pathways and mechanisms, one of which being cardiac disorders. Atrial cardiopathy (AC) is a structural and functional disorder of the left atrium that may be a substrate for other cardiac disorders such as atrial fibrillation (AF) and heart failure (HF). The association between AF and HF and cognitive decline is clear; however, the relationship between AC and cognition requires further investigation. Studies have shown that several markers of AC, such as increased brain natriuretic peptide and left atrial enlargement, are associated with an increased risk for cognitive impairment. The pathophysiology of cognitive decline in patients with AC is not yet well understood. Advancing our understanding of the relationship between AC and cognition may point to important treatable targets and inform future therapeutic advancements. This review presents our current understanding of the diagnosis of AC, as well as clinical characteristics and potential pathways involved in the association between AC and cognitive impairment.

Gut microbiota in sarcopenia and heart failure

Sarcopenia is common in aging and in patients with heart failure (HF) who may experience worse outcomes. Patients with muscle wasting are more likely to experience falls and can have serious complications when undergoing cardiac procedures. While intensive nutritional support and exercise rehabilitation can help reverse some of these changes, they are often under-prescribed in a timely manner, and we have limited insights into who would benefit. Mechanistic links between gut microbial metabolites (GMM) have been identified and may contribute to adverse clinical outcomes in patients with cardio-renal diseases and aging. This review will examine the emerging evidence for the influence of the gut microbiome-derived metabolites and notable signaling pathways involved in both sarcopenia and HF, especially those linked to dietary intake and mitochondrial metabolism. This provides a unique opportunity to gain mechanistic and clinical insights into developing novel therapeutic strategies that target these GMM pathways or through tailored nutritional modulation to prevent progressive muscle wasting in elderly patients with heart failure.

Melatonin as an Anti-Aging Therapy for Age-Related Cardiovascular and Neurodegenerative Diseases

The concept of “aging” is defined as the set of gradual and progressive changes in an organism that leads to an increased risk of weakness, disease, and death. This process may occur at the cellular and organ level, as well as in the entire organism of any living being. During aging, there is a decrease in biological functions and in the ability to adapt to metabolic stress. General effects of aging include mitochondrial, cellular, and organic dysfunction, immune impairment or inflammaging, oxidative stress, cognitive and cardiovascular alterations, among others. Therefore, one of the main harmful consequences of aging is the development and progression of multiple diseases related to these processes, especially at the cardiovascular and central nervous system levels. Both cardiovascular and neurodegenerative pathologies are highly disabling and, in many cases, lethal. In this context, melatonin, an endogenous compound naturally synthesized not only by the pineal gland but also by many cell types, may have a key role in the modulation of multiple mechanisms associated with aging. Additionally, this indoleamine is also a therapeutic agent, which may be administered exogenously with a high degree of safety. For this reason, melatonin could become an attractive and low-cost alternative for slowing the processes of aging and its associated diseases, including cardiovascular and neurodegenerative disorders.

Genome-wide transcript and protein analysis highlights the role of protein homeostasis in the aging mouse heart

Investigation of the molecular mechanisms of aging in the human heart is challenging because of confounding factors, such as diet and medications, as well as limited access to tissues from healthy aging individuals. The laboratory mouse provides an ideal model to study aging in healthy individuals in a controlled environment. However, previous mouse studies have examined only a narrow range of the genetic variation that shapes individual differences during aging. Here, we analyze transcriptome and proteome data from 185 genetically diverse male and female mice at ages 6, 12, and 18 mo to characterize molecular changes that occur in the aging heart. Transcripts and proteins reveal activation of pathways related to exocytosis and cellular transport with age, whereas processes involved in protein folding decrease with age. Additional changes are apparent only in the protein data including reduced fatty acid oxidation and increased autophagy. For proteins that form complexes, we see a decline in correlation between their component subunits with age, suggesting age-related loss of stoichiometry. The most affected complexes are themselves involved in protein homeostasis, which potentially contributes to a cycle of progressive breakdown in protein quality control with age. Our findings highlight the important role of post-transcriptional regulation in aging. In addition, we identify genetic loci that modulate age-related changes in protein homeostasis, suggesting that genetic variation can alter the molecular aging process.

Genetic and environmental determinants of diastolic heart function

Diastole is the sequence of physiological events that occur in the heart during ventricular filling and principally depends on myocardial relaxation and chamber stiffness. Abnormal diastolic function is related to many cardiovascular disease processes and is predictive of health outcomes, but its genetic architecture is largely unknown. Here, we use machine learning cardiac motion analysis to measure diastolic functional traits in 39,559 participants of the UK Biobank and perform a genome-wide association study. We identified 9 significant, independent loci near genes that are associated with maintaining sarcomeric function under biomechanical stress and genes implicated in the development of cardiomyopathy. Age, sex and diabetes were independent predictors of diastolic function and we found a causal relationship between genetically-determined ventricular stiffness and incident heart failure. Our results provide insights into the genetic and environmental factors influencing diastolic function that are relevant for identifying causal relationships and potential tractable targets.

Application of Mesenchymal Stem Cells During Machine Perfusion: An Emerging Novel Strategy for Organ Preservation

Although solid organ transplantation remains the definitive management for patients with end-stage organ failure, this ultimate treatment has been limited by the number of acceptable donor organs. Therefore, efforts have been made to expand the donor pool by utilizing marginal organs from donation after circulatory death or extended criteria donors. However, marginal organs are susceptible to ischemia-reperfusion injury (IRI) and entail higher requirements for organ preservation. Recently, machine perfusion has emerged as a novel preservation strategy for marginal grafts. This technique continually perfuses the organs to mimic the physiologic condition, allows the evaluation of pretransplant graft function, and more excitingly facilitates organ reconditioning during perfusion with pharmacological, gene, and stem cell therapy. As mesenchymal stem cells (MSCs) have anti-oxidative, immunomodulatory, and regenerative properties, mounting studies have demonstrated the therapeutic effects of MSCs on organ IRI and solid organ transplantation. Therefore, MSCs are promising candidates for organ reconditioning during machine perfusion. This review provides an overview of the application of MSCs combined with machine perfusion for lung, kidney, liver, and heart preservation and reconditioning. Promising preclinical results highlight the potential clinical translation of this innovative strategy to improve the quality of marginal grafts.

Age and Sex Differences in Heart Failure With Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is a multi-organ disorder that represents about 50% of total heart failure (HF) cases and is the most common form of HF in the elderly. Because of its increasing prevalence caused by the aging population, high mortality and morbidity, and very limited therapeutic options, HFpEF is considered as one of the greatest unmet medical needs in cardiovascular medicine. Despite its complex pathophysiology, numerous preclinical models have been established in rodents and in large animals to study HFpEF pathophysiology. Although age and sex differences are well described in HFpEF population, there are knowledge gaps in sex- and age-specific differences in established preclinical models. In this review, we summarize various strategies that have been used to develop HFpEF models and discuss the knowledge gaps in sex and age differences in HFpEF.