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.

Epigenetic Mechanisms Involved in Inflammaging-Associated Hypertension

PURPOSE OF REVIEW

This review summarizes the involvement of inflammaging in vascular damage with focus on the epigenetic mechanisms by which inflammaging-induced hypertension is triggered.

RECENT FINDINGS

Inflammaging in hypertension is a complex condition associated with the production of inflammatory mediators by the immune cells, enhancement of oxidative stress, and tissue remodeling in vascular smooth muscle cells and endothelial cells. Cellular processes are numerous, including inflammasome assembly and cell senescence which may involve mitochondrial dysfunction, autophagy, DNA damage response, dysbiosis, and many others. More recently, a series of noncoding RNAs, mainly microRNAs, have been described as possessing epigenetic actions on the regulation of inflammasome-related hypertension, emerging as a promising therapeutic strategy. Although there are a variety of pharmacological agents that effectively regulate inflammaging-related hypertension, a deeper understanding of the epigenetic events behind the control of vessel deterioration is needed for the treatment or even to prevent the disease onset.

Association of Titin Variations With Late-Onset Dilated Cardiomyopathy

IMPORTANCE

Dilated cardiomyopathy (DCM) is frequently caused by genetic factors. Studies identifying deleterious rare variants have predominantly focused on early-onset cases, and little is known about the genetic underpinnings of the growing numbers of patients with DCM who are diagnosed when they are older than 60 years (ie, late-onset DCM).

OBJECTIVE

To investigate the prevalence, type, and prognostic impact of disease-associated rare variants in patients with late-onset DCM.

DESIGN, SETTING, AND PARTICIPANTS

A population of patients with late-onset DCM who had undergone genetic testing in 7 international tertiary referral centers worldwide were enrolled from March 1990 to August 2020. A positive genotype was defined as the presence of pathogenic or likely pathogenic (P/LP) variants.

MAIN OUTCOMES AND MEASURES

The study outcome was all-cause mortality.

RESULTS

A total of 184 patients older than 60 years (103 female [56%]; mean [SD] age, 67 [6] years; mean [SD] left ventricular ejection fraction, 32% [10%]) were studied. Sixty-six patients (36%) were carriers of a P/LP variant. Titin-truncating variants were the most prevalent (present in 46 [25%] of the total population and accounting for 46 [69%] of all genotype-positive patients). During a median (interquartile range) follow-up of 42 (10-115) months, 23 patients (13%) died; 17 (25%) of these were carriers of P/LP variants, while 6 patients (5.1%) were genotype-negative.

CONCLUSIONS AND RELEVANCE

Late-onset DCM might represent a distinct subgroup characterized by and a high genetic variation burden, largely due to titin-truncating variants. Patients with a positive genetic test had higher mortality than genotype-negative patients. These findings support the extended use of genetic testing also in older patients.

Is heart failure with preserved ejection fraction a 'dementia' of the heart?

Heart failure with preserved ejection fraction (HFpEF) remains an elusive entity, due to its heterogeneous clinical profile and an arbitrarily defined nosology. Several pathophysiological mechanisms recognized as central for the development of HFpEF appear to be in common with the process of physiological aging of the heart. Both conditions are characterized by progressive impairment in cardiac function, accompanied by left ventricular hypertrophy, diastolic dysfunction, sarcomeric, and metabolic abnormalities. The neurological paradigm of dementia-intended as a progressive, multifactorial organ damage with decline of functional reserve, eventually leading to irreversible dysfunction-is well suited to represent HFpEF. In such perspective, certain phenotypes of HFpEF may be viewed as a maladaptive response to environmental modifiers, causing premature and pathological aging of the heart. We here propose that the 'HFpEF syndrome' may reflect the interplay of adverse structural remodelling and erosion of functional reserve, mirroring the processes leading to dementia in the brain. The resulting conceptual framework may help advance our understanding of HFpEF and unravel potential therapeutical targets.

Influence of ageing on circadian rhythm of heart rate variability in healthy subjects

BACKGROUND

The analysis of the circadian rhythm of heart rate variability (HRV) represents a relevant physiological tool to assess the vagal system. However, the influence of age (mostly >75 years) on HRV is not widely known.

AIMS

The aim of this study was to evaluate the influence of age on HRV, particularly in the elderly and to identify a model of this relationship. The study was carried out by examining linear and nonlinear parameters extracted from HRV, including individuals over 75 years for which there is no research available.

METHODS

Data from 140 healthy subjects were sex matched and divided into young (young group: 15-39 years old), adult (adult group: 40-64 years old) and senior (senior group: 65-90 years old) groups. 24-h Holter monitoring was used and several HRV parameters were extracted from time, and spectral and nonlinear analyses were examined.

RESULTS

Time-domain parameters, mainly standard deviation of the NN interval (SDNN) and number of successive differences of intervals which differ by more than 50 ms, presented significant differences between the young group and the other two groups during the 24-h period, while normalized spectral parameters (LFn, HFn and low frequency/high frequency), as well as nonlinear parameters, mainly β exponent and fractal dimension, showed significant difference between the senior group and the other two groups. All these parameters showed a similar circadian rhythm with significant differences between the mean day and night values, especially in young and adult group cohorts. Moreover, a parabolic relationship between these parameters and age was highlighted with an opposite trend over about 60 years compared with younger people.

CONCLUSION

A progressive physiological autonomic imbalance is present in ageing. The inverse trend in the relation between HRV parameters and age found in the senior group could be mainly due to a faster fluctuation of RR. This should be considered when studying changes in the cardiac autonomic nervous control.

Sex-Specific Prognostic Implications in Dilated Cardiomyopathy After Left Ventricular Reverse Remodeling

BACKGROUND

Women affected by Dilated Cardiomyopathy (DCM) experience better outcomes compared to men. Whether a more pronounced Left Ventricular Reverse Remodelling (LVRR) might explain this is still unknown.

AIM

We investigated the relationship between LVRR and sex and its long-term outcomes.

METHODS

A cohort of 605 DCM patients with available follow-up data was consecutively enrolled. LVRR was defined, at 24-month follow-up evaluation, as an increase in left ventricular ejection fraction (LVEF) ≥ 10% or a LVEF > 50% and a decrease ≥ 10% in indexed left ventricular end-diastolic diameter (LVEDDi) or an LVEDDi ≤ 33 mm/m². Outcome measures were a composite of all-cause mortality/heart transplantation (HTx) or ventricular assist device (VAD) and a composite of Sudden Cardiac Death (SCD) or Major Ventricular Arrhythmias (MVA).

RESULTS

181 patients (30%) experienced LVRR. The cumulative incidence of LVRR at 24-months evaluation was comparable between sexes (33% vs. 29%; p = 0.26). During a median follow-up of 149 months, women experiencing LVRR had the lowest rate of main outcome measure (global p = 0.03) with a 71% relative risk reduction compared to men with LVRR, without significant difference between women without LVRR and males. A trend towards the same results was found regarding SCD/MVA (global p = 0.06). Applying a multi-state model, male sex emerged as an independent adverse prognostic factor even after LVRR completion.

CONCLUSIONS

Although the rate of LVRR was comparable between sexes, females experiencing LVRR showed the best outcomes in the long term follow up compared to males and females without LVRR. Further studies are advocated to explain this difference in outcomes between sexes.

Echocardiographic evaluation of centenarians in Trieste

BACKGROUND

Population aging has increased together with the need for cardiovascular care. Understanding the relevance of cardiovascular conditions in the very old is crucial to developing a specific and rationale therapeutic approach. Centenarians can be considered a model of successful aging, although the impact of cardiovascular disease in this population is still unclear.

AIM

To evaluate the cardiovascular health status of a subset of centenarians enrolled in the Centenari a Trieste study and living in the province of Trieste to describe the prevalence of cardiovascular conditions among them.

METHODS

The current study included 20 individuals born before 1919 and living in the province of Trieste as of 1 May 2019. All centenarians were able to give consent and were subjected to an in-home complete clinical assessment focused on cardiovascular conditions, ECG and echocardiography.

RESULTS

The majority of centenarians were women (85%) and were not taking any chronic cardiovascular medication (55%). No centenarians had a history of ischemic heart disease while about one-third had signs suggestive of heart failure at examination (20%). Atrial fibrillation was present in 20% of individuals and conduction disorders were uncommon. Although the majority of individuals had a preserved left ventricular function, diastolic function was abnormal in 80% of enrolled centenarians that, however, was mild in 73% of cases.

CONCLUSION

This is the second study to perform in-home echocardiography in centenarians and the first to characterize the cardiovascular status of centenarians living in Trieste. The majority of centenarians had asymptomatic diastolic dysfunction and were naïve from cardiovascular therapy. The recruitment of new individuals from the Trieste area is continuing to perform analyses on clinical, genetic and environmental factors that may predict greater longevity in this geographical context and unveil mechanisms that regulate cardiac aging associated with increased lifespan.

Aging Attenuates Cardiac Contractility and Affects Therapeutic Consequences for Myocardial Infarction

Cardiac function of the human heart changes with age. The age-related change of systolic function is subtle under normal conditions, but abrupt under stress or in a pathogenesis state. Aging decreases the cardiac tolerance to stress and increases susceptibility to ischemia, which caused by aging-induced Ca2+ transient impairment and metabolic dysfunction. The changes of contractility proteins and the relative molecules are in a non-linear fashion. Specifically, the expression and activation of cMLCK increase first then fall during ischemia and reperfusion (I/R). This change is responsible for the nonmonotonic contractility alteration in I/R which the underlying mechanism is still unclear. Contractility recovery in I/R is also attenuated by age. The age-related change in cardiac contractility influences the therapeutic effect and intervention timepoint. For most cardiac ischemia therapies, the therapeutic result in the elderly is not identical to the young. Anti-aging treatment has the potential to prevent the development of ischemic injury and improves cardiac function. In this review we discuss the mechanism underlying the contractility changes in the aged heart and age-induced ischemic injury. The potential mechanism underlying the increased susceptibility to ischemic injury in advanced age is highlighted. Furthermore, we discuss the effect of age and the administration time for intervention in cardiac ischemia therapies.

Extracellular matrix roles in cardiorenal fibrosis: Potential therapeutic targets for CVD and CKD in the elderly

Whereas hypertension, diabetes, and dyslipidemia are age-related risk factors for cardiovascular disease (CVD) and chronic kidney disease (CKD), aging alone is an independent risk factor. With advancing age, the heart and kidney gradually but significantly undergo inflammation and subsequent fibrosis, which eventually results in an irreversible decline in organ physiology. Through cardiorenal network interactions, cardiac dysfunction leads to and responds to renal injury, and both facilitate aging effects. Thus, a comprehensive strategy is needed to evaluate the cardiorenal aging network. Common hallmarks shared across systems include extracellular matrix (ECM) accumulation, along with upregulation of matrix metalloproteinases (MMPs) including MMP-9. The wide range of MMP-9 substrates, including ECM components and inflammatory cytokines, implicates MMP-9 in a variety of pathological and age-related processes. In particular, there is strong evidence that inflammatory cell-derived MMP-9 exacerbates cardiorenal aging. This review explores the potential therapeutic targets against CVD and CKD in the elderly, focusing on ECM and MMP roles.

Cardiovascular aging: the unveiled enigma from bench to bedside

: The rapid increase in the median age of the world's population requires particular attention towards older and more fragile people. Cardiovascular risk factors, time and comorbidities play a vicious role in the development of heart failure, both with reduced and preserved ejection fraction, in the elderly. Understanding the mechanisms underlying the pathophysiological processes observed with aging is pivotal to target those patients and their therapeutic needs properly. This review aims to investigate and to dissect the main pathways leading to the aging cardiomyopathy, helping to understand the relationship from bench to bedside of the clinical phenotype.

Premature senescence of cardiac fibroblasts and atrial fibrosis in patients with atrial fibrillation

Premature senescence is associated with atrial fibrosis and has an antifibrotic effect in mice. However, the role of senescence in atrial fibrillation (AF) remains unclear. Here, we investigated the association of premature senescence with fibrosis and also determined the role of senescence in the recurrence of AF after surgery ablation. Western blot, Sirius red staining, SA-β-gal staining and immunohistochemistry were performed to detect the degree of atrial fibrosis ,the expression of TGF-β and collagens, and also the senescence markers in 72 tissue specimens of left atrial appendage in this study. Then the patients undergoing successful surgical ablation were followed up for 12 months. The expression of collagens and TGF-β was paralleled by a high level of atrial fibrosis and were increased in AF group, especially in the persistent AF group. Western blotting of P16 and SA-β-gal staining showed an increased premature senescence in the sinus rhythm, paroxysmal AF and persistent AF groups. In addition, positive area of senescence markers, SA-β-gal and P16, was correlated positively with fibrotic lesions. We also found a lower ratio of P16/TGF-β in patients with recurrence of AF than in patients without recurrent AF. In conclusion, premature senescence is associated with atrial fibrosis in AF, and may have an antifibrotic role in AF.

Role of circulating factors in cardiac aging

Worldwide increase in life expectancy is a major contributor to the epidemic of chronic degenerative diseases. Aging, indeed, simultaneously affects multiple organ systems, and it has been hypothesized that systemic alterations in regulators of tissue physiology may regulate this process. Cardiac aging itself is a major risk factor for cardiovascular diseases and, because of the intimate relationship with the brain, may contribute to increase the risk of neurodegenerative disorders. Blood-borne factors may play a major role in this complex and still elusive process. A number of studies, mainly based on the revival of parabiosis, a surgical technique very popular during the 70s of the 20th century to study the effect of a shared circulation in two animals, have indeed shown the potential that humoral factors can control the aging process in different tissues. In this article we review the role of circulating factors in cardiovascular aging. A better understanding of these mechanisms may provide new insights in the aging process and provide novel therapeutic opportunities for chronic age-related disorders.