Pathways for salvage and protection of the heart under stress

REVIEW

Pathways for salvage and protection of the heartunder stress: novel routes for cardiac rejuvenationAntonio Cannata1,2†, Luca Camparini1†, Gianfranco Sinagra2, Mauro Giacca3, andFrancesco S. Loffredo1,2*

1Molecular Cardiology, International Centre for Genetic Engineering and Biotechnology, Padriciano, 99, 34149 Trieste, Italy; 2Division of Cardiology, University of Trieste, Trieste, Italy; and3Molecular Medicine, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy

Received 7 March 2016; revised 7 May 2016; accepted 10 May 2016

Time for primary review: 40 days

The world population is aging, and by 2017, there will be more people over the age of 65 than under age 5, and by 2050, two billion of the estimatednine billion people on Earth will be older than 60. Aging itself is a major cardiovascular risk factor, affecting morbidity and mortality of the agingpopulation. At the same time, aging increases the likelihood of the presence of other risk factors. The aged myocardium is characterized by severalstructural and functional progressive changes that impair its ability to respond appropriately to stressful conditions. Although some progress tounderstand the complex mechanisms that underlie these phenotypic changes, the molecular pathways that determine the balance between agingand rejuvenation in the aged myocardium still remain elusive. In this article, we review molecular mechanisms responsible for the phenotypicchanges observed with aging in the heart, providing insight into molecular pathways and pharmacological interventions that may rejuvenate theaged myocardium. A better understanding of these pathways is essential for determining their therapeutic potential in humans, improving the pos-sibility that the increase in life expectancy that we are observing will be accompanied by a parallel increase in healthspan.- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -Keywords Cardiac aging † Cardiac rejuvenation † Caloric restriction † Aging hormones † Cardiac hypertrophy

1. IntroductionThe age profile of the European Union is expected to change dramat-ically in the coming decades, and nearly one-third of the population willbe aged 65 or over by 2060 (http://ec.europa.eu/Ageingreport2012).

Despite some progress in recent years, aging, an evolutionary highlyconserved process, still remains poorly understood.1 Aging inevitablyleads to a progressive decline in cell and organ function2; however,broad differences in the rate of this process can be observed among in-dividuals. The constant gait of time that leads to progressive functionaldecline is defined as chronological aging, while the actual status of bio-logical systems and their potential regenerative and rejuvenative cap-acity are referred to as biological age.3 Usually, chronological agereflects the biological age, whereas, sometimes, biological age appearsto be interestingly lower.3 This issue is pivotal in understanding the roleof rejuvenation pathways in healthy aging.

Similar to what happens with chronological aging, an increase in themedian age of a population may not reflect an increased quality of life.This is essentially due to differences in aging itself and to the increasedoccurrence of age-related pathologies, which may affect quality of life.4

Therefore, it is crucial to consider that an increase in lifespan, defined as

the life expectancy of an individual, does not necessarily mean an in-crease in healthspan, the expectancy of a good quality of life.

Aging is associated with a higher prevalence of cardiovascular disease(CVD), cancer, degenerative disorders, and immune-mediated dis-eases, indicating a causative role of this poorly understood process indetermining these conditions.5

The cardiovascular system itself is highly affected by the aging pro-cess. As previously reported in the Framingham study, age is the pri-mary risk factor for CVD, with 22% increase in the risk of CVD each5-year increment over 65 years.6 Cardiovascular pathologies such asheart failure (HF), cardiomyopathies, ischaemic heart disease (IHD),cardiac valve abnormalities, and hypertension all appear to increasetheir burden with age.7

Although IHD still represents the leading cause of mortality in thewestern world, the development of novel techniques and the improve-ment of therapies have dramatically overthrown the age-standardizedmortality rates for this disease,8 while, as the population ages, chronicheart conditions have become more prevalent,9 in particular HF.

Although HF is traditionally characterized by progressive dilation ofthe left ventricle accompanied by depressed ejection fraction, namelyheart failure with reduced ejection fraction (HFrEF), in part because

* Corresponding author. Tel: +39 0403757375; fax: +39 040226555, E-mail: [email protected]† These authors contributed equally to this work.

Published on behalf of the European Society of Cardiology. All rights reserved. & The Author 2016. For permissions please email: [email protected].

Cardiovascular Research (2016) 111, 142–153doi:10.1093/cvr/cvw106

Dow

nloaded from https://academ

ic.oup.com/cardiovascres/article/111/2/142/2237298 by guest on 30 July 2022

http://ec.europa.eu/Ageingreport2012



of the increasing aging population, a growing epidemic of HF with nor-mal systolic function, the so-called heart failure with preserved ejectionfraction (HFpEF), has been observed,10 now representing �50% of pa-tients hospitalized for HF.11 – 13 The different profile of patients withHFpEF that more often are old, obese, diabetic, hypertensive, and fe-male, compared with patients with HFrEF,14 suggests different physio-pathologic determinants. Specific treatment strategies for diastolicdysfunction are very limited, with large clinical trials revealing disap-pointingly outcomes with drugs like angiotensin-converting enzyme in-hibitors or beta adrenergic blockers,15 which have been appliedsuccessfully for systolic HF.

Thus, considering the increase in life expectancy, understanding themolecular mechanisms that regulate aging is crucial to improve thehealthspan of the aging populations and reduce the socioeconomic im-pact of chronic diseases.

In this review, our main focus is to dissect the most important path-ways of myocardial aging to understand and underline the main clinic-ally relevant mechanism of the emerging age-related disease and tohighlight the possible rejuvenation pathways in cardiovascular biology.

2. Cardiac agingAging is a major cardiovascular risk factor, affecting morbidity and mor-tality of the aging population. At the same time, aging itself increases thelikelihood of the presence of other risk factors, i.e. hypertension, dysli-pidemia, and diabetes.7 Cardiovascular aging is characterized by severalstructural and functional changes that eventually impair the capability ofthe myocardium to properly accommodate to stressful conditions.16

Aging in humans is accompanied by a progressive deterioration of car-diac function, affecting in particular the diastolic filling properties,17 andthis decline is observed at as early as the age of 20 years in humans.18 By80 years of age, the reduction in early diastolic filling is as profound as50%.18

Cardiomyocyte hypertrophy, increased apoptosis, decreased myo-cyte number, and remodelling of the extracellular matrix (ECM), hall-marks of cardiac aging, contribute to reduced left ventricular (LV)compliance and to LV stiffening, pathognomonic of HFpEF.17,19,20 In-creased LV mass has been found both in humans21 and in animals22

of older age. Several studies highlighted the role of cardiomyocytehypertrophy as a translational hallmark of cardiac aging, being frequent-ly observed in either humans,23 mice,24 or rats.25 Myocyte hypertrophy,either primary or secondary to hypertension, increases passive stiffnessof the LV, which in turn may contribute to diastolic dysfunction.26

Similar changes have been observed in several animal models frominvertebrates to non-human primates, recapitulating numerous age-dependent cardiac remodelling and functional changes observed in hu-mans. In particular, rodents present age-dependent cardiomyocytehypertrophy associated with myocardial fibrosis and mitochondrialdysfunction, all concurring to impair LV filling properties.24,27,28 MouseLV mass and left atrial dimension increase with a linear age-dependenttrend, and functional impairment is caused by a decrease in fractionalshortening (FS) and diastolic function associated with a reduction inmyocardial performance index (MPI).20,29 Recent findings have high-lighted the importance of the short-lived African Killifish as an emergingmodel of aging,30 with a potential to provide insight into cardiacaging-related diseases. The short life of this fish may, however, re-present a limitation to study changes that naturally occur late in life.In the aging myocardium, the increased deposition of collagen, the aug-mented cross-linking, and the increased ratio of type I to type III

collagen coupled with decreased elastin content and increased fibro-nectin are the fundamental changes occurring with ECM remodellinginducing diastolic dysfunction.31 – 39 All these changes observed withaging may contribute to reduced exercise tolerance and to augmentedsusceptibility to signs and symptoms of HF20,40 and are responsible forthe phenotypical manifestation of HFpEF typical of the elderly.41 Withage, increased serum levels of angiotensin II (Ang-II), one of the mostimportant vascular modifiers involved with remodelling, fibrosis, andreactive oxygen species (ROS) production,25 are observed both inrats and in mice.24,42 Several studies have shown in mice that reducingpresynaptic choline transporter promotes age-dependent fibrosis andhypertrophy,43 and the type 5 adenylyl cyclase knock-out mice appearsto be protected from cardiac fibrosis and hypertrophy related toaging,28 confirming the detrimental role of excessive adrenergic stimu-lation in promoting cardiac aging.

In humans, similar cardiovascular changes are observed in geneticallydetermined accelerated aging pathologies like Down’s syndrome44 andthe Hutchinson–Gilford progeria syndrome.45 In Down’s syndrome,the incidence of HF is more than doubled.46 In progeria, the associationwith myocardial fibrosis, lipofuscin deposition, and myocardial hyper-trophy is more frequently observed.47,48

3. Anatomical, histological, andmolecular correlates of myocardialaging

3.1. Extracellular matrixAging results in ECM remodelling due to reduced collagen turnoverrates, increased levels of fibrillar collagen,49 elevated levels of collagenmRNA, and post-translational modifications of collagen, both in hu-mans and in animals.50 These changes increase the stiffness of the myo-cardium and mediate diastolic dysfunction. The impact of aging oncollagen type I underlines the complex interplay of bidimensional de-position of collagen and more specifically its tridimensional (3D) struc-ture in a 3D model of cardiac ECM.51

The balance between the matrix metalloproteinases (MMPs) andtheir tissue inhibitors (TIMPs) tightly regulates ECM composition,and the activity of transforming growth factor-b (TGF-b) plays a majorrole in determining a proteolytic balance that favours accumulation ofECM and transformation of fibroblast into their more active pheno-type, the myofibroblasts.52

Aging is characterized by a shift favouring ECM accumulation andmyofibroblast transformation associated with concentric remodellingand decreased LV diastolic function.52,53

Interestingly, in a mouse model of cardiac aging, selective deletion ofMMP-9 has been shown to improve angiogenesis, attenuate inflamma-tion, and ameliorate ECM remodelling,54 underlining the interconnec-tion between endothelial function and ECM composition.

Recently, Meyer et al. investigated the role of premature senescencein myocardial fibrosis in animal models of transverse aortic constrictionand b1-adrenoreceptor transgenic mice. Intriguingly, the authors con-cluded that premature senescence of myofibroblast could reduce thefibrotic burden and ameliorate the cardiac function marshalling therole of ‘prosenescence’ cardiotropic myofibroblast induction as a po-tential therapeutic target for cardiac aging.55

Clear understanding of the specific mechanism underlying the role ofmyofibroblast and ECM remodelling in cardiac aging needs further

Novel routes for cardiac rejuvenation 143D

ownloaded from

https://academic.oup.com

/cardiovascres/article/111/2/142/2237298 by guest on 30 July 2022

studies; however, the complex interplay between cardiomyocytes,endothelial cells, myofibroblasts, and ECM represents a possible thera-peutic target to prevent the cardiac manifestation of aging.

3.2. TitinTitin, the largest molecule in myocytes, modulates myocyte stiffnessthrough phosphorylation of its spring-like domain.56 Genetic mutationsof titin are highly related to the onset of several cardiomyopathies.57,58

Aging is associated with post-translational modifications of the spring-like domain of titin that contribute to decreased cardiomyocytecompliance and promote diastolic dysfunction.59 Recently, Zile et al. re-ported that patients with hypertension and HFpEF had increasedcollagen-dependent and titin-dependent stiffness, confirming the inter-action between these two factors in the development of diastolic dys-function in elderly.60 In old dogs, treatment with sildenafil alone andsildenafil plus brain natriuretic peptide (BNP) increased phosphoryl-ation level of decreased titin-based passive stiffness, ameliorating dia-stolic function.61 These findings strongly suggest that titin regulatesmyocyte stiffness and the complex interplay between cardiomyocytesand ECM is a possible therapeutic target to ameliorate cardiac aging.

3.3. Calcium homeostasisCalcium (Ca2+) has complex and wide pleiotropic effects in cardio-myocyte biology.

Increased beta adrenergic activity, observed with aging, alters Ca2+

cycling through phosphorylation of different sites, namely phospholam-ban, Ca2+/calmodulin-dependent protein kinase (CaMK), L-type Ca2+

channels, and Na+/Ca2+ exchanger (NCX), and also through de-creased expression of sarcoplasmic/endoplasmic reticulum Ca2+ AT-Pase (SERCA) and alteration in ryanodine receptors (RyRs).62,63

Howlett et al.64 demonstrated that, in preparation of isolated ventricu-lar myocytes from old mice, when compared with cells from youngmice, Ca2+ transient amplitudes are reduced, while occurrence ofCa2+ sparks increases. Activation of calcium–calmodulin (CaM)-dependent pathways leads to hypertrophic response in human cardio-myocytes.65 This pathway is activated by excessive Ca2+ load withinthe cytoplasm, partially due to increased calcium entry through non-selective cation channels, the so-called transient receptor potentialchannels (TRPCs), which modulate cardiac hypertrophy and fibroblastproliferation both in physiological condition and in aging.66

Inositol-1,4,5-triphosphate (IP3) receptors, responsible for the releaseof Ca2+ within the cytoplasm, are also increased in the myocardium of26-month-old rats compared with 5- and 15-month-old rats.66 Thesereceptors appear to be upregulated in failing human hearts, probablymediating cell fate in this setting.67 Thus, the complex interplay be-tween calcium-induced calcium release, store-operated calcium entry(SOCE), and TRPCs may participate in regional regulatory events pro-moting cardiac hypertrophy and affecting lusitropism in aged mice.68

Del Monte et al.69 have shown that adenoviral transfection of SER-CA2a restored contractile function in failing human cardiomyocytes.These data were subsequently confirmed by Schmidt et al.,70 showingthat transfection of SERCA2a is able to restore normal Ca2+ cyclingand ameliorate diastolic function in the senescent rat myocardium. Inaddition, activation of insulin-like growth factor 1 (IGF-1) in old animalsameliorated cardiomyocyte contractile dysfunction and increased theSERCA activity.71 Though promising, results in humans appear contro-versial. A Phase 1/Phase 2 clinical trial using an adeno-associated virus

serotype 1 (AAV1) vector carrying SERCA2a in patients with end-stageHF ameliorated LV geometry and reduced hospitalization times.72

These results inspired a Phase 2b trial; however, intracoronary admin-istration of AAV1/SERCA2a did not improve clinical outcomes in pa-tients with HFrEF.73 A clinical trial using the same strategy has beenrecently concluded in patients with end-stage HF with left ventricularassist device (LVAD) (https://clinicaltrials.gov/ct2/show/NCT00534703);however, the results are not available yet. In contrast, recent findings indi-cate a potential beneficial role of airway-based delivery of AAV1/SERCA2ato induce vascular SERCA2a overexpression in pulmonary arteries result-ing in amelioration of pulmonary haemodynamics and RV performance,74

potentially reopening the question regarding feasibility and efficiency ofthis type of therapy in the setting of HF. Indeed, many aspects relatedto the delivery methods, including the titre and amount of empty viral cap-sids as decoys for preformed AAV antibodies, may have influenced the re-sults of the different trials. These results encourage further investigationsto clarify the role of enhanced calcium handling in HF and at the same timeprovide evidence for a clear role of gene therapy in treating CVDs.

Interestingly, calcium homeostasis appears to be regulated by sexualhormones, specifically by testosterone.75 As recently highlighted, tes-tosterone concentration decreases with aging in men and is associatedwith poorer quality of life.76 Testosterone treatment has already shownto inhibit coronary plaque progression in IHD.77 In the setting of car-diac aging, treatment of older men with testosterone may amelioratecardiac contraction and calcium homeostasis, although the mechanismunderlining these effects has still to be clarified.75

3.4. Excitation–contraction coupling andlate Na currentIn the elderly, different adaptation mechanisms contribute to the gen-esis of arrhythmias and, in particular, of atrial fibrillation (AF), a com-mon hallmark of cardiac aging.78

Isolated atrial cardiomyocytes from old humans79 and old dogs80

present reduced activity of Ca2+-handling proteins and altered atrialCa2+ homeostasis when compared with young individuals, contributingto the genesis of AF.

Modulation of the action potential (AP) duration results in increasedCa2+ entry through L-Type Ca2+ channels providing inotropic sup-ports to the aged myocardium.81 Signore et al. demonstrated that agingis associated with an increase in the late Na+ current (INaL) in cardio-myocytes, which in turn prolongs the AP and alters Ca2+ cycling andmyocyte contractility. In vitro inhibition of INaL in old myocytes shor-tened the AP, corrected the kinetics of Ca2+ transients, and amelio-rated cell contraction and relaxation, while improving diastolicfunction both in mice and in dogs.82,83

Ranolazine, an INaL blocker, was demonstrated to prevent recur-rences of angina and improve exercise tolerance in patients with chron-ic IHD.84

Finally, in a model of hypertensive rats, blocking the INaL, througheither tetrodotoxin or ranolazine, ameliorated diastolic dysfunction re-ducing the end-diastolic pressure–volume relationship slope and en-hancing cardiomyocyte relaxation.85 Moreover, blockade of INaLslowed the progression of hypertensive HF through an improvementof ultrastructural and physiological defects.86

Taken together, all these observations highlight that defects in theelectromechanical properties of cardiomyocytes are crucial determi-nants altering cardiac performance in the elderly.

A. Cannata et al.144D

ownloaded from



https://clinicaltrials.gov/ct2/show/NCT00534703



3.5. Neurohormonal activationThe role of the renin–angiotensin–aldosterone system (RAAS) in car-diac pathophysiology is well established, and the modulation of this axisis pivotal in the management of patients affected by HF.87 Increased ac-tivity of RAAS leads to phenotypical manifestation of cardiac aging inanimal models,42 and treatment with angiotensin-converting enzymeinhibitors (ACE-I) or angiotensin receptor blockers (ARBs) is asso-ciated with prolonged lifespan of the treated animals.88

High levels of Ang-II in fibrotic human hearts are associated with car-diac aging phenotype,89 and inhibition of Ang-II signalling in aged ani-mals significantly reduces cardiac hypertrophy and myocardialfibrosis, improving survival.90

Ang-II increases endothelin-1 (ET-1) levels, and treatment withACE-I and ARBs is associated with decreased levels of ET-1, protectingagainst the effect of aging in the vascular system.91 Aging itself is alsoassociated with increased levels of ET-1.92 Local levels of ET-1 correl-ate with vasoconstrictor tone in peripheral arteries, which explain oneof the mechanisms of the increased incidence of hypertension withaging.93 This factor mediates TGF-b expression, leading to increasedcollagen deposition both in old humans and in old rats.94 At thesame time, ET-1 is also crucial to maintain normal cardiac functionand exerts its effect through reduction of superoxide and MMP-9levels.95

Interestingly, increased expression of Klotho gene, which has beenshown to increase lifespan in mice,96 appears to prevent up-regulationof ET-1 and peripheral vascular disease in hypertensive rats.97

Excessive levels of Ang-I and Ang-II stimulate the production of Ang1–9 and Ang 1–7 via endo- or carboxy-peptidases through ACE-2,98

which is up-regulated by ACE-I, drugs widely used in the elderly.99

ACE-2-mediated catabolism of Ang-II is likely to play a major role incardiovascular protection.100 Protective effects of Ang 1–7 go beyondthe blood pressure effects, are mediated through Mas receptors, andare also associated with reduced cardiomyocyte autophagy and oxida-tive stress.101 Moreover, the other catabolite of ACE-2, Ang 1–9, ap-pears to reduce Ang-II levels, competing with Ang-I at the ACE activesite, and increases circulating levels of Ang 1–7.102 The administrationof Ang 1–9 reduces cardiac hypertrophy and ameliorates cardiac func-tion in rats after coronary artery ligation,103 reducing cardiac fibrosisand improving endothelial function in hypertensive rats, effects that ap-pear independent of Mas receptor activation.102 This important path-way intercepts the most widely used therapeutic intervention inpatients with cardiovascular risk factors, ACE-I or ARBs. Determiningwhich compounds are capable to promote the production of these me-tabolites may provide an important therapeutic tool to halt the agingprocess.

In elderly patients, elevated levels of natriuretic peptides (NPs) arefound even in physiological conditions,104 and administration of atrialnatriuretic peptide (ANP) or chronic inhibition of neprilysin (NEP),the enzyme responsible for NPs degradation, appears to amelioratethe aging phenotype in animal models.105 Recently, in humans, a newdrug composed of valsartan and sacubitril, LCZ-696, which combinesthe favourable effect of angiotensin type 1 receptor (AT1R) blockersand NEP inhibition, demonstrated its favourable effects in the reductionof death or hospitalization for HF.106 Administration of this compoundreduces myocardial fibrosis and cardiac hypertrophy;107 reduces levelsof circulating high-sensitivity cardiac troponin,108 a marker of subtlemyocardium damage; and have several favourable effects on renaland cerebral functions in the setting of HFpEF.109 – 111 Thus, to further

investigate the role of this drug in patients affected by HFpEF, a Phase IIIclinical trial has been designed (https://clinicaltrials.gov/ct2/show/NCT01920711), results of which are expected by 2020.

3.6. Mitochondria and oxidative imbalanceIncreased inflammation with aging is characterized by increased geneexpressions of interleukin (IL)-1B, IL-6, tumour necrosis factor(TNF)-a, cyclooxygenase (COX)-2, and inducible nitric oxidesynthases (iNOS) resulting in augmented oxidative stress through gen-eration of ROS, ultimately contributing to the onset of cardiac aging.112

Chronic inflammation and excessive ROS production damage directlymitochondria, and the damage of mitochondria leads to increased ROSproduction, which results in a vicious circle affecting healthy aging.Aging also results in increased production and decreased detoxificationof mitochondrial ROS, directly damaging cardiomyocytes.113 Indeed,reduction of myocyte oxidative stress through overexpression of mito-chondrial catalase (mCAT) has protective effects against cardiac hyper-trophy and fibrosis ameliorating the aging phenotype.114

Accumulation of damaged mitochondria with aging is also secondaryto a reduction of mitophagy, a specific form of macroautophagy re-sponsible for the elimination of dysfunctional mitochondria.115 Clear-ance of dysfunctional mitochondria appears to be controlled byAMP-activated protein kinase (AMPK) and mammalian target of rapa-mycin (mTOR) complex 1 (mTORC1) balance,116 and indeed, activa-tion of AMPK or use of rapamycin, an inhibitor of the mTOR pathway,promotes beneficial autophagy.117

In addition, increased oxidative stress activates ECM remodelling andprofibrotic pathways directly through the activation of TGF-b1 path-way by the NADPH oxidase 4 (NOX4)-dependent generation ofH2O2 and the conversion of cardiac fibroblast to myofibroblast.118

Ang-II stimulates NOX4 on the mitochondrial membrane favouringthe vicious cycle of oxidative stress and mitochondrial damage, thuspromoting cardiac aging.119 Scavenging of ROS mediated by catalasetargeted to mitochondrial appears as a feasible therapeutic approachto attenuate cardiac ECM remodelling and ameliorate myocardial fibro-sis in aged mice hearts.24

With aging, mitochondrial dysfunction produces oxidative imbalancefavouring myocyte hypertrophy, ECM remodelling, and stimulatingmyofibroblast activity. All these aspects are crucial for the develop-ment of the aging phenotype, and interventions on these pathwaysmay prevent the progression of cardiac aging.

Some of these aspects appear to be modulated by AMPK–NAD-dependent deacetylase sirtuin (SIRT)-1 axis through NF-kB activity120

and through FoxO/DAF-16 and Nrf2/SKN-1 activation, enhancing cellsurvival.121

Thus, several potential targets have been proposed to amelioratemitochondrial dysfunction. Caloric restriction (CR) physiologically re-presses the mTOR pathway and activates AMPK.5 Salicylate and met-formin, drugs widely used in humans, activate AMPK either by adirect interaction or by increasing ADP:ATP ratio, respectively.122

Rapamycin mimics CR beneficial effects and extends lifespan, re-duces LV hypertrophy, improves diastolic function in mice,106 and pro-motes mitochondrial remodelling.123 An interesting Phase I clinical trialconducted in old adults with IHD treated with three different doses ofrapamycin and aimed to evaluate frailty and its effects onsenescence-associated secretory phenotype has been recently con-cluded (https://clinicaltrials.gov/ct2/show/results/NCT01649960);however, results from this study are not yet available. A positive result


ownloaded from







https://clinicaltrials.gov/ct2/show/results/NCT01649960



of this trial would contribute to enhance the evidence that mimickingthe effects of CR is clearly a potential therapy in age-related CVDs inhumans.

Coenzyme Q (mitoQ) and plastoquinone (SkQ1) have already de-monstrated to exert protective effects on mitochondria in models ofischaemia–reperfusion and on cardiac hypertrophy.124 Their role incardiac aging, however, has to be further investigated. Controversieson the potential pro-oxidative effects of mitoQ might halt, however,its broader use in the setting of cardiac aging.125

Statins, the most widely used lipid-lowering drugs, also exertanti-aging effects by improving the redox status through inhibitionof Rac1 and NADPH oxidase activity126 and by inhibiting telomere at-trition.127 Moreover, activation of peroxisome proliferator-activatedreceptors (PPARs), a superfamily of ligand-activated nuclear transcrip-tional factors, regulates energy homeostasis, reduces inflammation,inhibits oxidative stress and apoptosis, and mitigates the effects ofcardiac aging.128

Recently, a novel approach to deliver antioxidants to the inner mem-brane of the mitochondria using the Szeto-Schiller (SS) peptides wasshown to restore mitochondrial plasticity.129 These mitochondrial-targeted peptides ameliorate function of the organelle, improveenergetic properties, and reduce oxidative cell death,130 suggesting apossible role in targeting the effects of cardiac aging.

In summary, oxidative imbalance and mitochondrial dysfunction arekey modulators of cardiac aging. The potential role of proper antioxi-dant compounds and of several widely used drugs, which impact onmitochondrial dysfunction and reduce the oxidative burden, mayhelp promote positive effects to improve the aged phenotype.

3.7. Telomere and telomeraseThe telomere–telomerase axis has a controversial role in the progres-sion of the functional decline observed with cardiac aging.131 Telomericshortening is a biomarker of lifetime stress,132 and the stress-relatedtelomere attrition is responsible for accelerated aging.133 Short leuko-cyte telomere length (LTL) is a hallmark of aging1 and is associated withCVD.134 Interestingly, longer LTLs are associated with better cardio-pulmonary performance in humans, and, although the molecular mech-anism underlining this effect is still unclear,135 endurance-exercisetraining may improve the aging phenotype by promoting the expressionof telomere-regulating genes.136 No direct evidences indicate that telo-mere length correlates with mortality in humans; however, to confirmthe putative role of telomere length in aging, patients with autosomal-dominant dyskeratosis congenita have short telomeres due tomutations in the telomerase and show signs of premature aging and areduced lifespan.137 Similarly, in C57Bl/6 mice, knocking out either thetelomerase reverse transcriptase (TERT) or telomerase RNA compo-nent (TERC) of telomerase promotes accelerated aging and reduceslifespan of these animals.138,139 Furthermore, short telomeres are asso-ciated with reduced exercise-specific signalling mechanisms in mice.140

Specifically to cardiac aging, telomere attrition may impact on eitherthe replicative capacity of progenitor cells or directly cardiomyo-cytes.131 Telomere attrition activates p53 affecting mitochondrial func-tion in cardiomyocytes by repressing peroxisome PGC-1a andPGC-1b, thus promoting cardiac aging.141 Although the molecularpathway responsible for this interaction and the development of theaged phenotype has not yet been completely characterized,142,143

the telomere–p53–PGC–mitochondria axis represents a key modula-tor in the setting of human aging.141

4. Novel strategies to rejuvenatethe aged myocardium

4.1. Reversing age-related cardiachypertrophyThe evidence that circulating factors in a young individual can rejuven-ate the aging phenotypes has sparked a lot of interest in the scientificcommunity. A number of studies, mainly based on the revival of para-biosis, a surgical technique very popular during the 1970s to study theeffect of a shared circulation in two animals, have shown the potentialthat humoral factors can control the aging process in different tis-sues.144,145 Heterochronic parabiosis, a specific experimental proced-ure whereby two animals of different ages are joined together, hasshown the potential to reverse age-related cardiac hypertrophy inmice.146 By proteomics studies, growth differentiation factor 11(GDF11), a member of the activin/TGF-b superfamily, was identifiedas a factor that carries the potential to reverse cardiac hypertrophy.146

Recent publications,147,148 however, have raised questions about theage-dependent reduction of GDF11 and its antihypertrophic effect.The results of these non-confirmatory studies, however, have beenchallenged by Poggioli et al. in a recent publication.149 These apparentlyconflicting results can be explained by the lack of a specific detectionreagent that can reliably discriminate GDF11 from its homologousmyostatin (GDF8 or MSTN) and by differences in source and dosesof the recombinant proteins used.150 While the effect of GDF11 initial-ly seemed to be restricted to age-induced cardiac hypertrophy, Poggioliet al.149 showed that this factor also exerts a dose-dependent effect inreducing cardiac hypertrophy in young mice, extending its therapeuticpotential to different forms of cardiac hypertrophy. These findings inmice are also supported by data from a prospective cohort study show-ing how GDF11 and MSTN might have similar cardioprotective prop-erties in humans.151 Over 900 plasma samples in subjects with stablecoronary heart disease (CHD) from the Heart and Soul prospectiveobservational cohort were analysed using aptamers to measure the le-vels of circulating factors;151 because this assay does not discriminateGDF11 from GDF8, the authors indicate the circulating factor asGDF11/8. Results from this study have shown that older individualshave significantly lower levels of GDF11/8 and that a strong correlationis present between low plasma GDF11/8 concentrations and cardio-vascular and mortality outcomes,151 with significantly more cardiachypertrophy detected by echocardiography in individuals with low le-vels of the factor.

While it is attractive to imagine that systemic administration of anage-regulating factor could reverse the aging phenotype in humans, itis critical first to consider that the effects of sustained supernormal le-vels of those factors are unpredictable, especially when patients areyoung. Thus, a more specific approach to target specifically cardiomyo-cytes without interfering with circulating levels of aging hormones isnecessary.

4.2. MicroRNAsMicroRNAs (miRNAs) play a key role in regulating cardiovascular re-generation,152 aging, and remodelling.153,154

In Caenorhabditis elegans, lin-4 miRNA, which controls the develop-mental progression, appears to modulate lifespan and accelerate tissueaging. Indeed, loss of function of this miRNA shortens lifespan, whileknocking down the lin-4 target expands it. Moreover, several othermiRNAs, such as mir-71, mir-238, mir-239, and mir-246, have been


ownloaded from



associated with altered lifespan, and overexpression of mir-71 andmir-246 interestingly increases the lifespan of C. elegans.155,156

In mammals, several miRNAs have been associated with aging.Hooten et al. have shown that miR-151a-5p, miR-181a-5p, andmiR-1248 were significantly decreased in the serum of old humanscompared with their younger counterparts.157 These data were con-firmed also in non-human primates; however, their role in cardiovascu-lar biology needs to be further investigated.

Apoptosis and cellular senescence appear to be mediated bymiR-34a, a miRNA upregulated in cardiac aging,158 which inhibits pro-tein phosphatase-1 regulatory subunit-10 (PNUTS) exacerbating telo-mere attrition, DNA damage, and fibrosis.159 Cardiac fibroblast andfibrosis, instead, are modulated by two different miRNAs. miR-22 acti-vates cardiac fibroblast increasing their migration and senescence,160

whereas the miR-17–92 cluster activates TGF-b/connective tissuegrowth factor (CTGF) and trhrombospondin-1 pathways, regulatingECM remodelling.161 Efficacy of cardiac repair and angiogenesis is af-fected by loss of miR-126 and miR-130.162 Cardiac repair and angiogen-esis are also impaired by the increased senescence of endothelial stemcell due to the age-dependent increase of miR-10a and miR-21a.163

Taken together, these findings support the potential of miRNAs totreat cardiac aging. A major limitation could be represented by themultiplicity of targets of single miRNAs that may elicit unwanted effects.However, understanding their role in cardiac aging may help to identifyspecific targets to delay the onset of a dysfunctional aging myocardium.

4.3. Metabolism and antioxidantsLongevity pathways play an important role in regulating mitochondrialbiogenesis and function, in yeast and eukaryotes, including mammals,164

representing a critical biological aspect to promote healthy cardiacaging. This modulation is controlled mainly by PPAR-g coactivator1-a (PGC-1a),165 a potential target for correcting the effects of ageon mitochondrial dysfunction.

Nutrient uptake is also crucial in determining cardiac aging, and CRincreases lifespan and healthspan across the entire eukariota do-main.166 CR protects against heart disease, diabetes, cancer, obesity,and neurodegenerative disease167 and reduces age-dependent loss ofcardiac function, fibrosis, and apoptotic pathways activation, either asa preventive or a therapeutic approach in young and aged animals.168

Figure 1 Schematic representation of the mechanism involved in cardiac aging. Cardiac aging is characterized by several structural and functionalchanges. Excess of nutrients, increased oxidative stress reduction in age-regulating hormones, may contribute to progressive accumulation of dysfunc-tional mitochondria and reduced protein turnover and changes in ECM, characterized by increased deposition of collagen and phenotypical changes offibroblasts into myofibroblasts.


ownloaded from



CR decreases mitochondrial ROS production, reduces the cell meta-bolic rate, and triggers the activation of longevity pathways that improveorganism resistance to hostile conditions.5 Insulin/IGF-1/mTOR signal-ling pathway, nicotinamide adenine dinucleotide-dependent deacety-lases (sirtuins), and AMPK act as key nutrient sensors involved incardiac and organism longevity and are able to increase autophagy,stress resistance, genomic stability, and mitochondrial turnover.5 Sir-tuins, important key regulators of the aging process, retard cardiac agingin animal models.9 Conserved from lower organisms, such as yeast, flies,and worms to humans, the seven members of the sirtuins class of mo-lecules are diversely positioned in the nucleus and cytosol respondingto the cellular energy balance through their NAD+ cofactor.9 Sirtuinsdeacetylate PGC-1a favouring the expression of NAD synthetic en-zyme nicotinamide phosphoribosyltransferase and activating theAMPK activator kinase LKB1.169 On the other hand, SIRT1 reducesmetabolic turnover rate and represses HIF-1a.170 All these effects re-duce ROS formations and promote mitochondrial turnover. SRT1720and SRT2104 are two synthetic activators of SIRT1, capable of extend-ing mice lifespan and providing cardiovascular protection.171 SRT2104

has also been tested in clinical trials confirming safety and biological ac-tivity in elderly humans.172 Noteworthy, the role of SIRT1 activation iscontroversial.173 Mild overexpression of SIRT1 (up to 7.5-fold) reducesthe age-dependent cardiac dysfunction and remodelling induced by oxi-dative stress.9 However, 12.5-fold overexpression of SIRT1 increasesoxidative stress, promotes cardiomyocyte hypertrophy, and activatesapoptosis.9 Additionally, SIRT1 haploinsufficiency has a protectiverole against pressure overload-induced hypertrophy and failure.174

Resveratrol administration modulates and restores antioxidant cap-acity of the cells, improves mitochondrial function, and activates the sir-tuin pathways.175,176 Resveratrol treatment ameliorates cardiacfunction177 activating SIRT1 and reducing the pro-apoptotic signallingmediated by Foxo-1 in old animals.178 The role of resveratrol on car-diac aging in humans is still unclear.179

Physical activity also delays aging and promotes mitochondrial reju-venation in animal models.180 In particular, endurance-exercise trainingstimulates insulin sensitivity and energy expenditure; this results in in-creased median lifespan through activation of sirtuin and ameliorationof mitochondrial function.181

Figure 2 Schematic representation of the putative pathways to rejuvenate the aged myocardium. Therapeutic approaches that interfere with the mo-lecular pathways that are involved in cardiac aging have the potential to delay or reverse the onset of chronic cardiovascular conditions and reversecardiac dysfunction.


ownloaded from



Pharmacological interventions to redirect energy expenditure in fa-vour of cellular maintenance and repair may represent the hinge to haltand reverse cardiac aging. Further studies are needed to investigate themolecular pathways of these compounds; however, suggesting a cor-rect lifestyle to everyone appears to be the cornerstone to improvequality of life.

5. Future perspectives andconclusionsIn a world where the aging population is rapidly increasing, the recentprogress of our understanding of the molecular processes that regulatecardiovascular aging (Figure 1) has provided a novel and innovative ap-proach to reverse or delay age-related diseases (Figure 2). Although atheory that integrates all of the different intriguing observations inthe field of aging is still needed, recent studies have provided a numberof evidences indicating that a switch from energy expenditure for re-productive and biosynthetic needs towards maintenance and repaircould be the key to extend lifespan and healthspan. Several therapeuticapproaches that interfere with the molecular pathways that are in-volved in cardiac aging have shown the potential to delay or reversethe onset of chronic cardiovascular conditions and reverse cardiac dys-function. In particular, modulation of cardiac metabolism, organellesand proteins turnover, and gene expression using CR, pharmacologicaltherapy, recombinant proteins, and miRNAs represents a promisingstrategy that, however, still requires studies to evaluate its translationalpotential. It is important to consider that the majority of these ap-proaches lack cardiac specificity and have the potential to interferewith multiple pathways, with a significant risk of side effects. Thus, amore targeted approach together with a better understanding of thecomplex interactions that regulate biodistribution and biochemical ef-fects of these interventions is a fundamental step to determine theirtherapeutic potential.

The possibility to ‘rejuvenate’ the aged myocardium has enormousimplications in cardiovascular pathology, and it will favour the chancesthat the increase in life expectancy observed will be accompanied by aparallel increase in healthspan.

AcknowledgementsWe would like to dedicate this work to the memory of Professor Gui-do Tarone, whose attitude towards science has inspired and will inspirecardiovascular research.

Conflict of interest: none declared.

FundingThis work was supported by the International Centre for Genetic Engineer-ing and Biotechnology (ICGEB) General Fund.

References1. Lopez-Otin C, Blasco MA, Partridge L, Serrano M, Kroemer G. The hallmarks of aging.

Cell 2013;153:1194–1217.2. Oh J, Lee YD, Wagers AJ. Stem cell aging: mechanisms, regulators and therapeutic

opportunities. Nat Med 2014;20:870–880.3. Hertel J, Friedrich N, Wittfeld K, Pietzner M, Budde K, Van der Auwera S, Lohmann T,

Teumer A, Volzke H, Nauck M, Grabe HJ. Measuring biological age via metabonomics:the metabolic age score. J Proteome Res 2016;15:400–410.

4. De Luca d’Alessandro E, Bonacci S, Giraldi G. Aging populations: the health and qualityof life of the elderly. Clin Ter 2011;162:e13–e18.

5. North BJ, Sinclair DA. The intersection between aging and cardiovascular disease.Circ Res 2012;110:1097–1108.

6. Larson MG. Assessment of cardiovascular risk factors in the elderly: the FraminghamHeart Study. Stat Med 1995;14:1745–1756.

7. Mozaffarian D, Benjamin EJ, Go AS, Arnett DK, Blaha MJ, Cushman M, Das SR, deFerranti S, Despres JP, Fullerton HJ, Howard VJ, Huffman MD, Isasi CR,Jimenez MC, Judd SE, Kissela BM, Lichtman JH, Lisabeth LD, Liu S, Mackey RH,Magid DJ, McGuire DK, Mohler ER 3rd, Moy CS, Muntner P, Mussolino ME,Nasir K, Neumar RW, Nichol G, Palaniappan L, Pandey DK, Reeves MJ,Rodriguez CJ, Rosamond W, Sorlie PD, Stein J, Towfighi A, Turan TN, Virani SS,Woo D, Yeh RW, Turner MB, American Heart Association Statistics C, Stroke Statis-tics S. Heart Disease and Stroke Statistics-2016 Update: a report from the AmericanHeart Association. Circulation 2016;133:e38–e360.

8. Moran AE, Forouzanfar MH, Roth GA, Mensah GA, Ezzati M, Murray CJ, Naghavi M.Temporal trends in ischemic heart disease mortality in 21 world regions, 1980 to2010: the Global Burden of Disease 2010 study. Circulation 2014;129:1483–1492.

9. Alcendor RR, Gao S, Zhai P, Zablocki D, Holle E, Yu X, Tian B, Wagner T, Vatner SF,Sadoshima J. Sirt1 regulates aging and resistance to oxidative stress in the heart. CircRes 2007;100:1512–1521.

10. Desai A, Fang JC. Heart failure with preserved ejection fraction: hypertension, dia-betes, obesity/sleep apnea, and hypertrophic and infiltrative cardiomyopathy. HeartFail Clin 2008;4:87–97.

11. Ouzounian M, Lee DS, Liu PP. Diastolic heart failure: mechanisms and controversies.Nat Clin Pract Cardiovasc Med 2008;5:375–386.

12. Owan TE, Hodge DO, Herges RM, Jacobsen SJ, Roger VL, Redfield MM. Trends inprevalence and outcome of heart failure with preserved ejection fraction. N Engl JMed 2006;355:251–259.

13. Bhatia RS, Tu JV, Lee DS, Austin PC, Fang J, Haouzi A, Gong Y, Liu PP. Outcome ofheart failure with preserved ejection fraction in a population-based study. N Engl JMed 2006;355:260–269.

14. Owan TE, Redfield MM. Epidemiology of diastolic heart failure. Prog Cardiovasc Dis2005;47:320–332.

15. Paulus WJ. Novel strategies in diastolic heart failure. Heart 2010;96:1147–1153.16. Servick K. Biomedicine. Woes for ‘exercise hormone’. Science 2015;347:1299.17. Redfield MM, Jacobsen SJ, Borlaug BA, Rodeheffer RJ, Kass DA. Age- and gender-

related ventricular-vascular stiffening: a community-based study. Circulation 2005;112:2254–2262.

18. Dannenberg AL, Levy D, Garrison RJ. Impact of age on echocardiographic left ven-tricular mass in a healthy population (the Framingham Study). Am J Cardiol 1989;64:1066–1068.

19. Chen CH, Nakayama M, Nevo E, Fetics BJ, Maughan WL, Kass DA. Coupled systolic-ventricular and vascular stiffening with age: implications for pressure regulation andcardiac reserve in the elderly. J Am Coll Cardiol 1998;32:1221–1227.

20. Lakatta EG, Levy D. Arterial and cardiac aging: major shareholders in cardiovasculardisease enterprises: Part II: the aging heart in health: links to heart disease. Circulation2003;107:346–354.

21. Devereux RB, Alonso DR, Lutas EM, Gottlieb GJ, Campo E, Sachs I, Reichek N.Echocardiographic assessment of left ventricular hypertrophy: comparison tonecropsy findings. Am J Cardiol 1986;57:450–458.

22. Kiatchoosakun S, Restivo J, Kirkpatrick D, Hoit BD. Assessment of left ventricularmass in mice: comparison between two-dimensional and m-mode echocardiography.Echocardiography 2002;19:199–205.

23. Vasan RS, Sullivan LM, D’Agostino RB, Roubenoff R, Harris T, Sawyer DB, Levy D,Wilson PW. Serum insulin-like growth factor I and risk for heart failure in elderlyindividuals without a previous myocardial infarction: the Framingham Heart Study.Ann Intern Med 2003;139:642–648.

24. Dai DF, Santana LF, Vermulst M, Tomazela DM, Emond MJ, MacCoss MJ, Gollahon K,Martin GM, Loeb LA, Ladiges WC, Rabinovitch PS. Overexpression of catalasetargeted to mitochondria attenuates murine cardiac aging. Circulation 2009;119:2789–2797.

25. Wang M, Zhang J, Walker SJ, Dworakowski R, Lakatta EG, Shah AM. Involvement ofNADPH oxidase in age-associated cardiac remodeling. J Mol Cell Cardiol 2010;48:765–772.

26. Heinzel FR, Hohendanner F, Jin G, Sedej S, Edelmann F. Myocardial hypertrophy andits role in heart failure with preserved ejection fraction. J Appl Physiol (1985) 2015;119:1233–1242.

27. Treuting PM, Linford NJ, Knoblaugh SE, Emond MJ, Morton JF, Martin GM,Rabinovitch PS, Ladiges WC. Reduction of age-associated pathology in old mice byoverexpression of catalase in mitochondria. J Gerontol A Biol Sci Med Sci 2008;63:813–822.

28. Yan L, Vatner DE, O’Connor JP, Ivessa A, Ge H, Chen W, Hirotani S, Ishikawa Y,Sadoshima J, Vatner SF. Type 5 adenylyl cyclase disruption increases longevity andprotects against stress. Cell 2007;130:247–258.

29. Dai DF, Rabinovitch PS. Cardiac aging in mice and humans: the role of mitochondrialoxidative stress. Trends Cardiovasc Med 2009;19:213–220.

30. Kim Y, Nam HG, Valenzano DR. The short-lived African turquoise killifish: anemerging experimental model for ageing. Dis Model Mech 2016;9:115–129.

31. Barasch E, Gottdiener JS, Aurigemma G, Kitzman DW, Han J, Kop WJ, Tracy RP. Therelationship between serum markers of collagen turnover and cardiovascular out-come in the elderly: the Cardiovascular Health Study. Circ Heart Fail 2011;4:733–739.


ownloaded from



32. Borlaug BA, Paulus WJ. Heart failure with preserved ejection fraction: pathophysi-ology, diagnosis, and treatment. Eur Heart J 2011;32:670–679.

33. Eghbali M, Eghbali M, Robinson TF, Seifter S, Blumenfeld OO. Collagen accumulationin heart ventricles as a function of growth and aging. Cardiovasc Res 1989;23:723–729.

34. Gazoti Debessa CR, Mesiano Maifrino LB, Rodrigues de Souza R. Age related changesof the collagen network of the human heart. Mech Ageing Dev 2001;122:1049–1058.

35. Kitzman DW. Diastolic heart failure in the elderly. Heart Fail Rev 2002;7:17–27.36. Martos R, Baugh J, Ledwidge M, O’Loughlin C, Conlon C, Patle A, Donnelly SC,

McDonald K. Diastolic heart failure: evidence of increased myocardial collagenturnover linked to diastolic dysfunction. Circulation 2007;115:888–895.

37. Olivetti G, Giordano G, Corradi D, Melissari M, Lagrasta C, Gambert SR, Anversa P.Gender differences and aging: effects on the human heart. J Am Coll Cardiol 1995;26:1068–1079.

38. Olivetti G, Melissari M, Balbi T, Quaini F, Sonnenblick EH, Anversa P. Myocyte nuclearand possible cellular hyperplasia contribute to ventricular remodeling in thehypertrophic senescent heart in humans. J Am Coll Cardiol 1994;24:140–149.

39. Olivetti G, Melissari M, Capasso JM, Anversa P. Cardiomyopathy of the aging humanheart. Myocyte loss and reactive cellular hypertrophy. Circ Res 1991;68:1560–1568.

40. Swinne CJ, Shapiro EP, Jamart J, Fleg JL. Age-associated changes in left ventricular out-flow tract geometry in normal subjects. Am J Cardiol 1996;78:1070–1073.

41. Gottdiener JS, Bartz T, DeFilippi C, Kop W, Kitzman D, Barasch E, Seliger S,Lloyd-Jones D. Echocardiographic and biomarker phenotype of heart failure with pre-served ejection fraction (HFPEF) in older individuals in comparison to hypertensionwithout heart failure (HTN), elderly with risk factors, and healthy aging. Importance ofmyocyte injury, fibrosis, LV hypertrophy, and diastolic load. J Am Coll Cardiol 2012;59:E852–E852.

42. Groban L, Pailes NA, Bennett CD, Carter CS, Chappell MC, Kitzman DW,Sonntag WE. Growth hormone replacement attenuates diastolic dysfunction andcardiac angiotensin II expression in senescent rats. J Gerontol A Biol Sci Med Sci 2006;61:28–35.

43. English BA, Appalsamy M, Diedrich A, Ruggiero AM, Lund D, Wright J, Keller NR,Louderback KM, Robertson D, Blakely RD. Tachycardia, reduced vagal capacity,and age-dependent ventricular dysfunction arising from diminished expression ofthe presynaptic choline transporter. Am J Physiol Heart Circ Physiol 2010;299:H799–H810.

44. Horvath S, Garagnani P, Bacalini MG, Pirazzini C, Salvioli S, Gentilini D, Di Blasio AM,Giuliani C, Tung S, Vinters HV, Franceschi C. Accelerated epigenetic aging in Downsyndrome. Aging Cell 2015;14:491–495.

45. Ullrich NJ, Gordon LB. Hutchinson-Gilford progeria syndrome. Handb Clin Neurol2015;132:249–264.

46. Uppal H, Chandran S, Potluri R. Risk factors for mortality in Down syndrome. J IntellectDisabil Res 2015;59:873–881.

47. Reichel W, Garcia-Bunuel R. Pathologic findings in progeria: myocardial fibrosis andlipofuscin pigment. Am J Clin Pathol 1970;53:243–253.

48. Ilyas S, Ilyas H, Hameed A, Ilyas M. Progeria syndrome with cardiac complications. J PakMed Assoc 2013;63:1182–1185.

49. Bradshaw AD, Baicu CF, Rentz TJ, Van Laer AO, Bonnema DD, Zile MR. Age-dependent alterations in fibrillar collagen content and myocardial diastolic function:role of SPARC in post-synthetic procollagen processing. Am J Physiol Heart Circ Physiol2010;298:H614–H622.

50. Querejeta R, Lopez B, Gonzalez A, Sanchez E, Larman M, Martinez Ubago JL, Diez J.Increased collagen type I synthesis in patients with heart failure of hypertensive origin:relation to myocardial fibrosis. Circulation 2004;110:1263–1268.

51. Guilbert M, Roig B, Terryn C, Garnotel R, Jeannesson P, Sockalingum GD, Manfait M,Perraut F, Dinten JM, Koenig A, Piot O. Highlighting the impact of aging on type Icollagen: label-free investigation using confocal reflectance microscopy and diffusereflectance spectroscopy in 3D matrix model. Oncotarget 2016;7:8546–8555.

52. Brooks WW, Conrad CH. Myocardial fibrosis in transforming growth factorbeta(1)heterozygous mice. J Mol Cell Cardiol 2000;32:187–195.

53. Bonnema DD, Webb CS, Pennington WR, Stroud RE, Leonardi AE, Clark LL,McClure CD, Finklea L, Spinale FG, Zile MR. Effects of age on plasma matrix metallo-proteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs). J Card Fail2007;13:530–540.

54. Yabluchanskiy A, Ma Y, Chiao YA, Lopez EF, Voorhees AP, Toba H, Hall ME, Han HC,Lindsey ML, Jin YF. Cardiac aging is initiated by matrix metalloproteinase-9-mediatedendothelial dysfunction. Am J Physiol Heart Circ Physiol 2014;306:H1398–H1407.

55. Meyer K, Hodwin B, Ramanujam D, Engelhardt S, Sarikas A. Essential role for prema-ture senescence of myofibroblasts in myocardial fibrosis. J Am Coll Cardiol 2016;67:2018–2028.

56. Kruger M, Kotter S, Grutzner A, Lang P, Andresen C, Redfield MM, Butt E, dosRemedios CG, Linke WA. Protein kinase G modulates human myocardial passivestiffness by phosphorylation of the titin springs. Circ Res 2009;104:87–94.

57. Taylor M, Graw S, Sinagra G, Barnes C, Slavov D, Brun F, Pinamonti B, Salcedo EE,Sauer W, Pyxaras S, Anderson B, Simon B, Bogomolovas J, Labeit S, Granzier H,Mestroni L. Genetic variation in titin in arrhythmogenic right ventricularcardiomyopathy-overlap syndromes. Circulation 2011;124:876–885.

58. Herman DS, Lam L, Taylor MR, Wang L, Teekakirikul P, Christodoulou D, Conner L,DePalma SR, McDonough B, Sparks E, Teodorescu DL, Cirino AL, Banner NR,

Pennell DJ, Graw S, Merlo M, Di Lenarda A, Sinagra G, Bos JM, Ackerman MJ,Mitchell RN, Murry CE, Lakdawala NK, Ho CY, Barton PJ, Cook SA, Mestroni L,Seidman JG, Seidman CE. Truncations of titin causing dilated cardiomyopathy.N Engl J Med 2012;366:619–628.

59. Hamdani N, Bishu KG, von Frieling-Salewsky M, Redfield MM, Linke WA. Derangedmyofilament phosphorylation and function in experimental heart failure withpreserved ejection fraction. Cardiovasc Res 2013;97:464–471.

60. Zile MR, Baicu CF, Ikonomidis JS, Stroud RE, Nietert PJ, Bradshaw AD, Slater R,Palmer BM, Van Buren P, Meyer M, Redfield MM, Bull DA, Granzier HL,LeWinter MM. Myocardial stiffness in patients with heart failure and a preservedejection fraction: contributions of collagen and titin. Circulation 2015;131:1247–1259.

61. Bishu K, Hamdani N, Mohammed SF, Kruger M, Ohtani T, Ogut O, Brozovich FV,Burnett JC Jr, Linke WA, Redfield MM. Sildenafil and B-type natriuretic peptide acutelyphosphorylate titin and improve diastolic distensibility in vivo. Circulation 2011;124:2882–2891.

62. Janczewski AM, Lakatta EG. Modulation of sarcoplasmic reticulum Ca(2+) cycling insystolic and diastolic heart failure associated with aging. Heart Fail Rev 2010;15:431–445.

63. Babusikova E, Lehotsky J, Dobrota D, Racay P, Kaplan P. Age-associated changes inCa(2+)-ATPase and oxidative damage in sarcoplasmic reticulum of rat heart. PhysiolRes 2012;61:453–460.

64. Howlett SE, Grandy SA, Ferrier GR. Calcium spark properties in ventricular myocytesare altered in aged mice. Am J Physiol Heart Circ Physiol 2006;290:H1566–H1574.

65. Bers DM. Calcium cycling and signaling in cardiac myocytes. Annu Rev Physiol 2008;70:23–49.

66. Kaplan P, Jurkovicova D, Babusikova E, Hudecova S, Racay P, Sirova M, Lehotsky J,Drgova A, Dobrota D, Krizanova O. Effect of aging on the expression of intracellularCa(2+) transport proteins in a rat heart. Mol Cell Biochem 2007;301:219–226.

67. Signore S, Sorrentino A, Ferreira-Martins J, Kannappan R, Shafaie M, Del Ben F,Isobe K, Arranto C, Wybieralska E, Webster A, Sanada F, Ogorek B, Zheng H,Liu X, Del Monte F, D’Alessandro DA, Wunimenghe O, Michler RE, Hosoda T,Goichberg P, Leri A, Kajstura J, Anversa P, Rota M. Inositol 1, 4, 5-trisphosphate re-ceptors and human left ventricular myocytes. Circulation 2013;128:1286–1297.

68. Eder P, Molkentin JD. TRPC channels as effectors of cardiac hypertrophy. Circ Res2011;108:265–272.

69. del Monte F, Harding SE, Schmidt U, Matsui T, Kang ZB, Dec GW, Gwathmey JK,Rosenzweig A, Hajjar RJ. Restoration of contractile function in isolated cardiomyo-cytes from failing human hearts by gene transfer of SERCA2a. Circulation 1999;100:2308–2311.

70. Schmidt U, del Monte F, Miyamoto MI, Matsui T, Gwathmey JK, Rosenzweig A,Hajjar RJ. Restoration of diastolic function in senescent rat hearts through adenoviralgene transfer of sarcoplasmic reticulum Ca(2+)-ATPase. Circulation 2000;101:790–796.

71. Li Q, Wu S, Li SY, Lopez FL, Du M, Kajstura J, Anversa P, Ren J. Cardiac-specific over-expression of insulin-like growth factor 1 attenuates aging-associated cardiac diastoliccontractile dysfunction and protein damage. Am J Physiol Heart Circ Physiol 2007;292:H1398–H1403.

72. Zsebo K, Yaroshinsky A, Rudy JJ, Wagner K, Greenberg B, Jessup M, Hajjar RJ. Long-term effects of AAV1/SERCA2a gene transfer in patients with severe heart failure:analysis of recurrent cardiovascular events and mortality. Circ Res 2014;114:101–108.

73. Greenberg B, Butler J, Felker GM, Ponikowski P, Voors AA, Desai AS, Barnard D,Bouchard A, Jaski B, Lyon AR, Pogoda JM, Rudy JJ, Zsebo KM. Calcium upregulationby percutaneous administration of gene therapy in patients with cardiac disease(CUPID 2): a randomised, multinational, double-blind, placebo-controlled, phase 2btrial. Lancet 2016;387:1178–1186.

74. Aguero J, Ishikawa K, Hadri L, Santos-Gallego CG, Fish KM, Kohlbrenner E,Hammoudi N, Kho C, Lee A, Ibanez B, Garcia-Alvarez A, Zsebo K, Maron BA,Plataki M, Fuster V, Leopold JA, Hajjar RJ. Intratracheal gene delivery of SERCA2aameliorates chronic post-capillary pulmonary hypertension: a large animal model.J Am Coll Cardiol 2016;67:2032–2046.

75. Ayaz O, Howlett SE. Testosterone modulates cardiac contraction and calciumhomeostasis: cellular and molecular mechanisms. Biol Sex Differ 2015;6:9.

76. Snyder PJ, Bhasin S, Cunningham GR, Matsumoto AM, Stephens-Shields AJ, Cauley JA,Gill TM, Barrett-Connor E, Swerdloff RS, Wang C, Ensrud KE, Lewis CE, Farrar JT,Cella D, Rosen RC, Pahor M, Crandall JP, Molitch ME, Cifelli D, Dougar D,Fluharty L, Resnick SM, Storer TW, Anton S, Basaria S, Diem SJ, Hou X,Mohler ER, Parsons JK, Wenger NK, Zeldow B, Landis JR, Ellenberg SS. Effects ofTestosterone Treatment in Older Men. N Engl J Med 2016;374:611–624.

77. Abd Alamir M, Ellenberg SS, Swerdloff RS, Wenger NK, Mohler ER 3rd, Lewis CE,Barrett-Conner E, Nakanishi R, Darabian S, Alani A, Matsumoto S, Nezarat N,Snyder PJ, Budoff MJ. The cardiovascular trial of the testosterone trials: rationale,design, and baseline data of a clinical trial using computed tomographic imaging toassess the progression of coronary atherosclerosis. Coron Artery Dis 2016;27:95–103.

78. Kannel WB, Benjamin EJ. Current perceptions of the epidemiology of atrial fibrillation.Cardiol Clin 2009;27:13–24, vii.

79. Herraiz-Martinez A, Alvarez-Garcia J, Llach A, Molina CE, Fernandes J, Ferrero-Gregori A, Rodriguez C, Vallmitjana A, Benitez R, Padro JM, Martinez-Gonzalez J,


ownloaded from



Cinca J, Hove-Madsen L. Ageing is associated with deterioration of calcium homeo-stasis in isolated human right atrial myocytes. Cardiovasc Res 2015;106:76–86.

80. Xu GJ, Gan TY, Tang BP, Chen ZH, Jiang T, Song JG, Guo X, Li JX. Age-related changesin cellular electrophysiology and calcium handling for atrial fibrillation. J Cell Mol Med2013;17:1109–1118.

81. Sah R, Ramirez RJ, Kaprielian R, Backx PH. Alterations in action potential profileenhance excitation-contraction coupling in rat cardiac myocytes. J Physiol 2001;533:201–214.

82. Signore S, Sorrentino A, Borghetti G, Cannata A, Meo M, Zhou Y, Kannappan R,Pasqualini F, O’Malley H, Sundman M, Tsigkas N, Zhang E, Arranto C,Mangiaracina C, Isobe K, Sena BF, Kim J, Goichberg P, Nahrendorf M, Isom LL,Leri A, Anversa P, Rota M. Late Na(+) current and protracted electrical recoveryare critical determinants of the aging myopathy. Nat Commun 2015;6:8803.

83. Sorrentino A, Signore S, Qanud K, Borghetti G, Meo M, Cannata A, Zhou Y,Wybieralska E, Luciani M, Kannappan R, Zhang E, Matsuda A, Webster A,Cimini M, Kertowidjojo E, D’Alessandro DA, Wunimenghe O, Michler RE,Royer CM, Goichberg P, Leri A, Barrett EG, Anversa P, Hintze TH, Rota M. Myocyterepolarization modulates myocardial function in aging dogs. Am J Physiol Heart CircPhysiol 2016;310:H873–H890.

84. Chaitman BR, Skettino SL, Parker JO, Hanley P, Meluzin J, Kuch J, Pepine CJ, Wang W,Nelson JJ, Hebert DA, Wolff AA, Investigators M. Anti-ischemic effects and long-termsurvival during ranolazine monotherapy in patients with chronic severe angina. J AmColl Cardiol 2004;43:1375–1382.

85. Williams S, Pourrier M, McAfee D, Lin S, Fedida D. Ranolazine improves diastolic func-tion in spontaneously hypertensive rats. Am J Physiol Heart Circ Physiol 2014;306:H867–H881.

86. Aistrup GL, Gupta DK, Kelly JE, O’Toole MJ, Nahhas A, Chirayil N, Misener S,Beussink L, Singh N, Ng J, Reddy M, Mongkolrattanothai T, El-Bizri N, Rajamani S,Shryock JC, Belardinelli L, Shah SJ, Wasserstrom JA. Inhibition of the late sodium cur-rent slows t-tubule disruption during the progression of hypertensive heart disease inthe rat. Am J Physiol Heart Circ Physiol 2013;305:H1068–H1079.

87. McMurray JJ, Adamopoulos S, Anker SD, Auricchio A, Bohm M, Dickstein K, Falk V,Filippatos G, Fonseca C, Gomez-Sanchez MA, Jaarsma T, Kober L, Lip GY,Maggioni AP, Parkhomenko A, Pieske BM, Popescu BA, Ronnevik PK, Rutten FH,Schwitter J, Seferovic P, Stepinska J, Trindade PT, Voors AA, Zannad F, Zeiher A,Guidelines ESCCfP. ESC Guidelines for the diagnosis and treatment of acute andchronic heart failure 2012: The Task Force for the Diagnosis and Treatment of Acuteand Chronic Heart Failure 2012 of the European Society of Cardiology. Developed incollaboration with the Heart Failure Association (HFA) of the ESC. Eur Heart J 2012;33:1787–1847.

88. Basso N, Cini R, Pietrelli A, Ferder L, Terragno NA, Inserra F. Protective effect of long-term angiotensin II inhibition. Am J Physiol Heart Circ Physiol 2007;293:H1351–H1358.

89. Schnee JM, Hsueh WA. Angiotensin II, adhesion, and cardiac fibrosis. Cardiovasc Res2000;46:264–268.

90. Benigni A, Corna D, Zoja C, Sonzogni A, Latini R, Salio M, Conti S, Rottoli D,Longaretti L, Cassis P, Morigi M, Coffman TM, Remuzzi G. Disruption of the Ang IItype 1 receptor promotes longevity in mice. J Clin Invest 2009;119:524–530.

91. Ma LJ, Nakamura S, Whitsitt JS, Marcantoni C, Davidson JM, Fogo AB. Regression ofsclerosis in aging by an angiotensin inhibition-induced decrease in PAI-1. Kidney Int2000;58:2425–2436.

92. Donato AJ, Gano LB, Eskurza I, Silver AE, Gates PE, Jablonski K, Seals DR. Vascularendothelial dysfunction with aging: endothelin-1 and endothelial nitric oxide synthase.Am J Physiol Heart Circ Physiol 2009;297:H425–H432.

93. Thijssen DH, Rongen GA, van Dijk A, Smits P, Hopman MT. Enhanced endothelin-1-mediated leg vascular tone in healthy older subjects. J Appl Physiol (1985) 2007;103:852–857.

94. Wang X, Guo Z, Ding Z, Khaidakov M, Lin J, Xu Z, Sharma SG, Jiwani S, Mehta JL.Endothelin-1 upregulation mediates aging-related cardiac fibrosis. J Mol Cell Cardiol2015;80:101–109.

95. Hathaway CK, Grant R, Hagaman JR, Hiller S, Li F, Xu L, Chang AS, Madden VJ,Bagnell CR, Rojas M, Kim HS, Wu B, Zhou B, Smithies O, Kakoki M. Endothelin-1 crit-ically influences cardiac function via superoxide-MMP9 cascade. Proc Natl Acad Sci USA2015;112:5141–5146.

96. Kurosu H, Yamamoto M, Clark JD, Pastor JV, Nandi A, Gurnani P, McGuinness OP,Chikuda H, Yamaguchi M, Kawaguchi H, Shimomura I, Takayama Y, Herz J,Kahn CR, Rosenblatt KP, Kuro-o M. Suppression of aging in mice by the hormoneKlotho. Science 2005;309:1829–1833.

97. Wang Y, Sun Z. Antiaging gene Klotho regulates endothelin-1 levels and endothelinreceptor subtype B expression in kidneys of spontaneously hypertensive rats.J Hypertens 2014;32:1629–1636; discussion 1636.

98. Westermeier F, Bustamante M, Pavez M, Garcia L, Chiong M, Ocaranza MP,Lavandero S. Novel players in cardioprotection: Insulin like growth factor-1,angiotensin-(1–7) and angiotensin-(1–9). Pharmacol Res 2015;101:41–55.

99. Vuille-dit-Bille RN, Camargo SM, Emmenegger L, Sasse T, Kummer E, Jando J,Hamie QM, Meier CF, Hunziker S, Forras-Kaufmann Z, Kuyumcu S, Fox M,Schwizer W, Fried M, Lindenmeyer M, Gotze O, Verrey F. Human intestine luminalACE2 and amino acid transporter expression increased by ACE-inhibitors. AminoAcids 2015;47:693–705.

100. Jiang F, Yang J, Zhang Y, Dong M, Wang S, Zhang Q, Liu FF, Zhang K, Zhang C.Angiotensin-converting enzyme 2 and angiotensin 1–7: novel therapeutic targets.Nat Rev Cardiol 2014;11:413–426.

101. Lin L, Liu X, Xu J, Weng L, Ren J, Ge J, Zou Y. Mas receptor mediates cardioprotectionof angiotensin-(1–7) against Angiotensin II-induced cardiomyocyte autophagy andcardiac remodelling through inhibition of oxidative stress. J Cell Mol Med 2016;20:48–57.

102. Flores-Munoz M, Work LM, Douglas K, Denby L, Dominiczak AF, Graham D,Nicklin SA. Angiotensin-(1–9) attenuates cardiac fibrosis in the stroke-prone spon-taneously hypertensive rat via the angiotensin type 2 receptor. Hypertension 2012;59:300–307.

103. Ocaranza MP, Lavandero S, Jalil JE, Moya J, Pinto M, Novoa U, Apablaza F, Gonzalez L,Hernandez C, Varas M, Lopez R, Godoy I, Verdejo H, Chiong M. Angiotensin-(1–9)regulates cardiac hypertrophy in vivo and in vitro. J Hypertens 2010;28:1054–1064.

104. Lelli D, Pedone C, Rossi FF, Incalzi RA. Clinical and echocardiographic characteristicsof elderly hospitalized patients with high levels of NT-proBNP without clinical diagno-sis of heart failure. Aging Clin Exp Res 2014;26:607–613.

105. Thomas CJ, McAllen RM, Salo LM, Woods RL. Restorative effect of atrial natriureticpeptide or chronic neutral endopeptidase inhibition on blunted cardiopulmonaryvagal reflexes in aged rats. Hypertension 2008;52:696–701.

106. McMurray JJ, Packer M, Desai AS, Gong J, Lefkowitz MP, Rizkala AR, Rouleau JL,Shi VC, Solomon SD, Swedberg K, Zile MR, Investigators P-H, Committees.Angiotensin-neprilysin inhibition versus enalapril in heart failure. N Engl J Med 2014;371:993–1004.

107. von Lueder TG, Wang BH, Kompa AR, Huang L, Webb R, Jordaan P, Atar D, Krum H.Angiotensin receptor neprilysin inhibitor LCZ696 attenuates cardiac remodeling anddysfunction after myocardial infarction by reducing cardiac fibrosis and hypertrophy.Circ Heart Fail 2015;8:71–78.

108. Jhund PS, Claggett BL, Voors AA, Zile MR, Packer M, Pieske BM, Kraigher-Krainer E,Shah AM, Prescott MF, Shi V, Lefkowitz M, McMurray JJ, Solomon SD, Investigators P.Elevation in high-sensitivity troponin T in heart failure and preserved ejection fractionand influence of treatment with the angiotensin receptor neprilysin inhibitor LCZ696.Circ Heart Fail 2014;7:953–959.

109. Bai HY, Mogi M, Nakaoka H, Kan-No H, Tsukuda K, Chisaka T, Wang XL, Kukida M,Shan BS, Yamauchi T, Higaki A, Iwanami J, Horiuchi M. Pre-treatment with LCZ696, anorally active angiotensin receptor neprilysin inhibitor, prevents ischemic brain dam-age. Eur J Pharmacol 2015;762:293–298.

110. Wang BH, von Lueder TG, Kompa AR, Huang L, Webb R, Jordaan P, Atar D, Krum H.Combined angiotensin receptor blockade and neprilysin inhibition attenuatesangiotensin-II mediated renal cellular collagen synthesis. Int J Cardiol 2015;186:104–105.

111. Voors AA, Gori M, Liu LC, Claggett B, Zile MR, Pieske B, McMurray JJ, Packer M, Shi V,Lefkowitz MP, Solomon SD, Investigators P. Renal effects of the angiotensin receptorneprilysin inhibitor LCZ696 in patients with heart failure and preserved ejection frac-tion. Eur J Heart Fail 2015;17:510–517.

112. Fearon IM, Faux SP. Oxidative stress and cardiovascular disease: novel tools give (free)radical insight. J Mol Cell Cardiol 2009;47:372–381.

113. Terzioglu M, Larsson NG. Mitochondrial dysfunction in mammalian ageing. NovartisFound Symp 2007;287:197–208; discussion 208–113.

114. Dai DF, Chen T, Wanagat J, Laflamme M, Marcinek DJ, Emond MJ, Ngo CP, Prolla TA,Rabinovitch PS. Age-dependent cardiomyopathy in mitochondrial mutator mice is at-tenuated by overexpression of catalase targeted to mitochondria. Aging Cell 2010;9:536–544.

115. Wang K, Klionsky DJ. Mitochondria removal by autophagy. Autophagy 2011;7:297–300.

116. Lee J, Giordano S, Zhang J. Autophagy, mitochondria and oxidative stress: cross-talkand redox signalling. Biochem J 2012;441:523–540.

117. Russell RC, Yuan HX, Guan KL. Autophagy regulation by nutrient signaling. Cell Res2014;24:42–57.

118. Cucoranu I, Clempus R, Dikalova A, Phelan PJ, Ariyan S, Dikalov S, Sorescu D.NAD(P)H oxidase 4 mediates transforming growth factor-beta1-induced differenti-ation of cardiac fibroblasts into myofibroblasts. Circ Res 2005;97:900–907.

119. Dai DF, Johnson SC, Villarin JJ, Chin MT, Nieves-Cintron M, Chen T, Marcinek DJ,Dorn GW 2nd, Kang YJ, Prolla TA, Santana LF, Rabinovitch PS. Mitochondrialoxidative stress mediates angiotensin II-induced cardiac hypertrophy and Galphaqoverexpression-induced heart failure. Circ Res 2011;108:837–846.

120. Yeung F, Hoberg JE, Ramsey CS, Keller MD, Jones DR, Frye RA, Mayo MW.Modulation of NF-kappaB-dependent transcription and cell survival by the SIRT1 dea-cetylase. EMBO J 2004;23:2369–2380.

121. Salminen A, Kaarniranta K. AMP-activated protein kinase (AMPK) controls the agingprocess via an integrated signaling network. Ageing Res Rev 2012;11:230–241.

122. Hardie DG. AMPK: a target for drugs and natural products with effects on bothdiabetes and cancer. Diabetes 2013;62:2164–2172.

123. Chiao YA, Kolwicz SC, Basisty N, Gagnidze A, Zhang J, Gu H, Djukovic D, Beyer RP,Raftery D, MacCoss M, Tian R, Rabinovitch PS. Rapamycin transiently induces mito-chondrial remodeling to reprogram energy metabolism in old hearts. Aging (AlbanyNY) 2016;8:314–327.


ownloaded from



124. Szeto HH, James LP, Atkinson AJ. Mitochondrial pharmacology: its future is now. ClinPharmacol Ther 2014;96:629–633.

125. Murphy MP, Smith RA. Targeting antioxidants to mitochondria by conjugation to lipo-philic cations. Annu Rev Pharmacol Toxicol 2007;47:629–656.

126. Antoniades C, Bakogiannis C, Tousoulis D, Reilly S, Zhang MH, Paschalis A,Antonopoulos AS, Demosthenous M, Miliou A, Psarros C, Marinou K, Sfyras N,Economopoulos G, Casadei B, Channon KM, Stefanadis C. Preoperative atorvastatintreatment in CABG patients rapidly improves vein graft redox state by inhibition ofRac1 and NADPH-oxidase activity. Circulation 2010;122:S66–S73.

127. Olivieri F, Mazzanti I, Abbatecola AM, Recchioni R, Marcheselli F, Procopio AD,Antonicelli R. Telomere/telomerase system: a new target of statins pleiotropic effect?Curr Vasc Pharmacol 2012;10:216–224.

128. Barlaka E, Galatou E, Mellidis K, Ravingerova T, Lazou A. Role of pleiotropic proper-ties of peroxisome proliferator-activated receptors in the heart: focus on the nonme-tabolic effects in cardiac protection. Cardiovasc Ther 2016;34:37–48.

129. Szeto HH, Birk AV. Serendipity and the discovery of novel compounds that restoremitochondrial plasticity. Clin Pharmacol Ther 2014;96:672–683.

130. Birk AV, Liu S, Soong Y, Mills W, Singh P, Warren JD, Seshan SV, Pardee JD, Szeto HH.The mitochondrial-targeted compound SS-31 re-energizes ischemic mitochondria byinteracting with cardiolipin. J Am Soc Nephrol 2013;24:1250–1261.

131. Moslehi J, DePinho RA, Sahin E. Telomeres and mitochondria in the aging heart. CircRes 2012;110:1226–1237.

132. Mitchell C, Hobcraft J, McLanahan SS, Siegel SR, Berg A, Brooks-Gunn J, Garfinkel I,Notterman D. Social disadvantage, genetic sensitivity, and children’s telomere length.Proc Natl Acad Sci USA 2014;111:5944–5949.

133. Geronimus AT, Hicken MT, Pearson JA, Seashols SJ, Brown KL, Cruz TD. Do US blackwomen experience stress-related accelerated biological aging?: a novel theory andfirst population-based test of black-white differences in telomere length. Hum Nat2010;21:19–38.

134. Huzen J, de Boer RA, van Veldhuisen DJ, van Gilst WH, van der Harst P. The emergingrole of telomere biology in cardiovascular disease. Front Biosci (Landmark Ed) 2010;15:35–45.

135. Loprinzi PD. Cardiorespiratory capacity and leukocyte telomere length among adultsin the United States. Am J Epidemiol 2015;182:198–201.

136. Denham J, O’Brien BJ, Prestes PR, Brown NJ, Charchar FJ. Increased expression oftelomere-regulating genes in endurance athletes with long leukocyte telomeres.J Appl Physiol (1985) 2016;120:148–158.

137. Kirwan M, Dokal I. Dyskeratosis congenita, stem cells and telomeres. Biochim BiophysActa 2009;1792:371–379.

138. Wong LS, Oeseburg H, de Boer RA, van Gilst WH, van Veldhuisen DJ, van der Harst P.Telomere biology in cardiovascular disease: the TERC-/- mouse as a model for heartfailure and ageing. Cardiovasc Res 2009;81:244–252.

139. Blasco MA, Lee HW, Hande MP, Samper E, Lansdorp PM, DePinho RA, Greider CW.Telomere shortening and tumor formation by mouse cells lacking telomerase RNA.Cell 1997;91:25–34.

140. Ludlow AT, Roth SM. Physical activity and telomere biology: exploring the link withaging-related disease prevention. J Aging Res 2011;2011:790378.

141. Sahin E, Colla S, Liesa M, Moslehi J, Muller FL, Guo M, Cooper M, Kotton D, Fabian AJ,Walkey C, Maser RS, Tonon G, Foerster F, Xiong R, Wang YA, Shukla SA, Jaskelioff M,Martin ES, Heffernan TP, Protopopov A, Ivanova E, Mahoney JE, Kost-Alimova M,Perry SR, Bronson R, Liao R, Mulligan R, Shirihai OS, Chin L, DePinho RA. Telomeredysfunction induces metabolic and mitochondrial compromise. Nature 2011;470:359–365.

142. Sahin E, Depinho RA. Linking functional decline of telomeres, mitochondria and stemcells during ageing. Nature 2010;464:520–528.

143. Chin L, Artandi SE, Shen Q, Tam A, Lee SL, Gottlieb GJ, Greider CW, DePinho RA.p53 Deficiency rescues the adverse effects of telomere loss and cooperates with telo-mere dysfunction to accelerate carcinogenesis. Cell 1999;97:527–538.

144. Villeda SA, Plambeck KE, Middeldorp J, Castellano JM, Mosher KI, Luo J, Smith LK,Bieri G, Lin K, Berdnik D, Wabl R, Udeochu J, Wheatley EG, Zou B, Simmons DA,Xie XS, Longo FM, Wyss-Coray T. Young blood reverses age-related impairmentsin cognitive function and synaptic plasticity in mice. Nat Med 2014;20:659–663.

145. Katsimpardi L, Litterman NK, Schein PA, Miller CM, Loffredo FS, Wojtkiewicz GR,Chen JW, Lee RT, Wagers AJ, Rubin LL. Vascular and neurogenic rejuvenation ofthe aging mouse brain by young systemic factors. Science 2014;344:630–634.

146. Loffredo FS, Steinhauser ML, Jay SM, Gannon J, Pancoast JR, Yalamanchi P, Sinha M,Dall’osso C, Khong D, Shadrach JL, Miller CM, Singer BS, Stewart A, Psychogios N,Gerszten RE, Hartigan AJ, Kim MJ, Serwold T, Wagers AJ, Lee RT. Growth differenti-ation factor 11 is a circulating factor that reverses age-related cardiac hypertrophy.Cell 2013;153:828–839.

147. Egerman MA, Cadena SM, Gilbert JA, Meyer A, Nelson HN, Swalley SE, Mallozzi C,Jacobi C, Jennings LL, Clay I, Laurent G, Ma S, Brachat S, Lach-Trifilieff E,Shavlakadze T, Trendelenburg AU, Brack AS, Glass DJ. GDF11 increases with ageand inhibits skeletal muscle regeneration. Cell Metabol 2015;22:164–174.

148. Smith SC, Zhang X, Zhang X, Gross P, Starosta T, Mohsin S, Franti M, Gupta P,Hayes D, Myzithras M, Kahn J, Tanner J, Weldon SM, Khalil A, Guo X, Sabri A,Chen X, MacDonnell S, Houser SR. GDF11 does not rescue aging-related pathologic-al hypertrophy. Circ Res 2015;117:926–932.

149. Poggioli T, Vujic A, Yang P, Macias-trevino C, Uygur A, Loffredo S, Pancoast JR, Cho M,Goldstein J, Tandias RM, Walker RG, Thompson TB, Wagers AJ, Fong YW, Richard T,Lee RT. Circulating growth differentiation factor 11 / 8 levels decline with age. Circ Res2016;118:29–37.

150. McNally EM. Questions and answers about myostatin, GDF11, and the aging heart.Circ Res 2016;118:6–8.

151. Olson KA, Beatty AL, Heidecker B, Regan MC, Brody EN, Foreman T, Kato S,Mehler RE, Singer BS, Hveem K, Dalen H, Sterling DG, Lawn RM, Schiller NB,Williams SA, Whooley MA, Ganz P. Association of growth differentiation factor11/8, putative anti-ageing factor, with cardiovascular outcomes and overall mortalityin humans: analysis of the Heart and Soul and HUNT3 cohorts. Eur Heart J 2015;36:3426–3434.

152. Eulalio A, Mano M, Dal Ferro M, Zentilin L, Sinagra G, Zacchigna S, Giacca M. Func-tional screening identifies miRNAs inducing cardiac regeneration. Nature 2012;492:376–381.

153. Sayed D, Hong C, Chen IY, Lypowy J, Abdellatif M. MicroRNAs play an essential role inthe development of cardiac hypertrophy. Circ Res 2007;100:416–424.

154. Kumarswamy R, Thum T. Non-coding RNAs in cardiac remodeling and heart failure.Circ Res 2013;113:676–689.

155. Smith-Vikos T, Slack FJ. MicroRNAs and their roles in aging. J Cell Sci 2012;125:7–17.156. Jung HJ, Suh Y. MicroRNA in aging: from discovery to biology. Curr Genomics 2012;13:

548–557.157. Noren Hooten N, Fitzpatrick M, Wood WH 3rd, De S, Ejiogu N, Zhang Y,

Mattison JA, Becker KG, Zonderman AB, Evans MK. Age-related changes in micro-RNA levels in serum. Aging (Albany NY) 2013;5:725–740.

158. Boon RA, Iekushi K, Lechner S, Seeger T, Fischer A, Heydt S, Kaluza D, Treguer K,Carmona G, Bonauer A, Horrevoets AJ, Didier N, Girmatsion Z, Biliczki P,Ehrlich JR, Katus HA, Muller OJ, Potente M, Zeiher AM, Hermeking H, Dimmeler S.MicroRNA-34a regulates cardiac ageing and function. Nature 2013;495:107–110.

159. Loffredo FS, Pancoast JR, Lee RT. Keep PNUTS in your heart. Circ Res 2013;113:97–99.

160. Jazbutyte V, Fiedler J, Kneitz S, Galuppo P, Just A, Holzmann A, Bauersachs J, Thum T.MicroRNA-22 increases senescence and activates cardiac fibroblasts in the agingheart. Age (Dordr) 2013;35:747–762.

161. van Almen GC, Verhesen W, van Leeuwen RE, van de Vrie M, Eurlings C,Schellings MW, Swinnen M, Cleutjens JP, van Zandvoort MA, Heymans S,Schroen B. MicroRNA-18 and microRNA-19 regulate CTGF and TSP-1 expressionin age-related heart failure. Aging Cell 2011;10:769–779.

162. Jakob P, Doerries C, Briand S, Mocharla P, Krankel N, Besler C, Mueller M, Manes C,Templin C, Baltes C, Rudin M, Adams H, Wolfrum M, Noll G, Ruschitzka F,Luscher TF, Landmesser U. Loss of angiomiR-126 and 130a in angiogenic early out-growth cells from patients with chronic heart failure: role for impaired in vivo neovas-cularization and cardiac repair capacity. Circulation 2012;126:2962–2975.

163. Zhu S, Deng S, Ma Q, Zhang T, Jia C, Zhuo D, Yang F, Wei J, Wang L, Dykxhoorn DM,Hare JM, Goldschmidt-Clermont PJ, Dong C. MicroRNA-10A* and MicroRNA-21modulate endothelial progenitor cell senescence via suppressing high-mobility groupA2. Circ Res 2013;112:152–164.

164. Bonawitz ND, Shadel GS. Rethinking the mitochondrial theory of aging: the role ofmitochondrial gene expression in lifespan determination. Cell Cycle 2007;6:1574–1578.

165. Wenz T, Wang X, Marini M, Moraes CT. A metabolic shift induced by a PPAR pana-gonist markedly reduces the effects of pathogenic mitochondrial tRNA mutations.J Cell Mol Med 2011;15:2317–2325.

166. Fontana L, Partridge L, Longo VD. Extending healthy life span--from yeast to humans.Science 2010;328:321–326.

167. Longo VD, Mattson MP. Fasting: molecular mechanisms and clinical applications. CellMetab 2014;19:181–192.

168. Niemann B, Chen Y, Issa H, Silber RE, Rohrbach S. Caloric restriction delays cardiacageing in rats: role of mitochondria. Cardiovasc Res 2010;88:267–276.

169. Rodgers JT, Lerin C, Gerhart-Hines Z, Puigserver P. Metabolic adaptations throughthe PGC-1 alpha and SIRT1 pathways. FEBS Lett 2008;582:46–53.

170. Guarente L. Calorie restriction and sirtuins revisited. Genes Dev 2013;27:2072–2085.171. Hubbard BP, Sinclair DA. Small molecule SIRT1 activators for the treatment of aging

and age-related diseases. Trends Pharmacol Sci 2014;35:146–154.172. Libri V, Brown AP, Gambarota G, Haddad J, Shields GS, Dawes H, Pinato DJ,

Hoffman E, Elliot PJ, Vlasuk GP, Jacobson E, Wilkins MR, Matthews PM. A pilot rando-mized, placebo controlled, double blind phase I trial of the novel SIRT1 activatorSRT2104 in elderly volunteers. PloS One 2012;7:e51395.

173. Pillai VB, Sundaresan NR, Gupta MP. Regulation of Akt signaling by sirtuins: its impli-cation in cardiac hypertrophy and aging. Circ Res 2014;114:368–378.

174. Oka S, Alcendor R, Zhai P, Park JY, Shao D, Cho J, Yamamoto T, Tian B, Sadoshima J.PPARalpha-Sirt1 complex mediates cardiac hypertrophy and failure through suppres-sion of the ERR transcriptional pathway. Cell Metab 2011;14:598–611.

175. Lagouge M, Argmann C, Gerhart-Hines Z, Meziane H, Lerin C, Daussin F,Messadeq N, Milne J, Lambert P, Elliott P, Geny B, Laakso M, Puigserver P,Auwerx J. Resveratrol improves mitochondrial function and protects against metabol-ic disease by activating SIRT1 and PGC-1alpha. Cell 2006;127:1109–1122.


ownloaded from



176. Tung BT, Rodriguez-Bies E, Thanh HN, Le-Thi-Thu H, Navas P, Sanchez VM,Lopez-Lluch G. Organ and tissue-dependent effect of resveratrol and exercise onantioxidant defenses of old mice. Aging Clin Exp Res 2015;27:775–783.

177. Zhang Y, Mi SL, Hu N, Doser TA, Sun A, Ge J, Ren J. Mitochondrial aldehyde dehydro-genase 2 accentuates aging-induced cardiac remodeling and contractile dysfunction:role of AMPK, Sirt1, and mitochondrial function. Free Radic Biol Med 2014;71:208–220.

178. Sin TK, Yu AP, Yung BY, Yip SP, Chan LW, Wong CS, Ying M, Rudd JA, Siu PM. Modu-lating effect of SIRT1 activation induced by resveratrol on Foxo1-associated apoptoticsignalling in senescent heart. J Physiol 2014;592:2535–2548.

179. Tome-Carneiro J, Gonzalvez M, Larrosa M, Yanez-Gascon MJ, Garcia-Almagro FJ,Ruiz-Ros JA, Tomas-Barberan FA, Garcia-Conesa MT, Espin JC. Resveratrol in primaryand secondary prevention of cardiovascular disease: a dietary and clinical perspective.Ann N Y Acad Sci 2013;1290:37–51.

180. Safdar A, Bourgeois JM, Ogborn DI, Little JP, Hettinga BP, Akhtar M, Thompson JE,Melov S, Mocellin NJ, Kujoth GC, Prolla TA, Tarnopolsky MA. Endurance exerciserescues progeroid aging and induces systemic mitochondrial rejuvenation in mtDNAmutator mice. Proc Natl Acad Sci USA 2011;108:4135–4140.

181. Lanza IR, Short DK, Short KR, Raghavakaimal S, Basu R, Joyner MJ, McConnell JP, Nair KS.Endurance exercise as a countermeasure for aging. Diabetes 2008;57:2933–2942.


ownloaded from



Pathways for salvage and protection of the heart under stress

Documents

Transcript of Pathways for salvage and protection of the heart under stress