The Yin and Yang of Cellular Senescence in Ischemia-Induced Myocardial Injury

Abstract

Cellular senescence is a stress-responsive program that critically affects chronological and biological aging, ischemia-reperfusion injury (IRI), and age-related cardiovascular diseases. Of relevance, cardiac senescent cells exhibit altered characteristics that promote inflammation, remodeling, and fibrosis, ultimately contributing to the functional decline following myocardial infarction (MI). At the same time, emerging evidence suggests that senescence may also exert protective effects post-MI, limiting fibrosis. Thus, understanding the mechanisms and pathways of cardiac senescence appears critical for delineating the consequences of IRI, including identification of novel therapeutic targets for improving post-MI recovery.

Introduction

Acute myocardial infarction (MI) is a leading cause of mortality. MI is characterized by complex and progressive molecular and cellular transitions, recognized as post-MI cardiac remodeling(1). These transitions can lead to acute heart failure and sudden death or post-MI cardiomyopathies, which increase risk for chronic heart failure. Rapid reperfusion is key to the improvement of patient outcomes. However, reperfusion subsequent to ischemia can also contribute substantially to further cardiac damage. Studies have indicated that cellular senescence is a critical event subsequent to ischemia/reperfusion injury and that cellular senescence contributes to cardiac dysfunction and pathologic remodeling(2).

Cellular senescence is a cell fate that can be induced by various stressors. Characteristics of senescent cells include resistance to apoptosis and loss of physiological function. Moreover, senescent cells can release a broad range of pro-inflammatory factors, the so-called senescence associated secretory phenotype (SASP). SASP factors, in turn, can promote a pro-inflammatory state, contributing further to tissue dysfunction and the spread of cellular senescence to naïve cells, leading to further senescent cell accumulation. In the heart, senescent cells have been associated not only with aging but several cardiovascular diseases (CVDs) including coronary atherosclerosis(3), cardiac hypertrophy(4), cardiac fibrosis(5), and myocardial infarction(2).

Emerging evidence supports the notion that myocardial infarction induces cellular senescence in cardiomyocytes, fibroblasts, and endothelial cells and that this is linked to augmented release of SASP factors and declines in cardiac function(2, 6). Moreover, senescent cardiomyocytes have been found to contribute to cardiac remodeling following MI, promoting inflammation and the spread of cellular senescence(7).

Beyond its detrimental role in age-related cardiovascular disease, senescence may also have protective functions(8). Transient induction of senescence has been shown to support wound healing and tissue repair by halting proliferation and some senescent cells can secrete growth factors and facilitate immune-mediated clearance of damaged cells(9). As a consequence of transpositional mutations, senescent cells that are not removed can become increasingly pro-inflammatory and damaging over time, becoming persisting or late senescent cells(10). In the context of myocardial infarction, transient senescence in fibroblasts and cardiomyocytes may limit excessive fibrosis while reducing remodeling(5, 11–13), while if these transient senescent cells persist, the SASP shifts from being regenerative to maladaptive, driving chronic inflammation, fibrosis, and adverse remodeling(11, 14, 15).

Of note, aging hearts are at a higher risk for severe post-MI outcomes, in part due to a pre-existing burden of senescent cells(16). Here, we delineate consequences of cellular senescence following myocardial infarction, with a focus on pathophysiological consequences and the identification of novel therapeutic targets.

Cardiac Cellular Senescence

Cardiac senescence refers to several senescent cell types in the heart, including cardiomyocytes, fibroblasts, and endothelial cells, which contribute to cardiac aging phenotypes and development of several cardiovascular diseases, including heart failure and myocardial infarction(4, 17). Although cellular senescence was initially thought to be a cell cycle arrest process unique to proliferating cells, it has become evident that senescence represents a generalized response to many types of cellular stress and can also occur in postmitotic cells, including cardiomyocytes(4, 12).

Cardiomyocytes comprise ~30–40% of the total cardiac cellular population and 80% of the cellular volume(18). Senescent cardiomyocytes are characterized by persistent DNA damage in telomere regions, independently of telomere length, potentially driven by mitochondrial dysfunction and oxidative stress(4). Cardiomyocytes that turned senescent exhibited changes in their function, including impaired cell shortening, increased pacing frequency, and contractile and metabolic dysfunction(19). Of additional relevance is the secretion of SASP factors that induce senescence in neighboring cell types(19). Senescent cardiomyocytes display an upregulation of such classic senescence markers as p16, p21, and p53 and also express certain SASP factors, including cellular communication network protein family member 1 (CCN1), interleukins (IL1α, IL1β, and IL6), tumor necrosis factor-alpha (TNFα), monocyte chemoattractant protein-1 (MCP1), endothelin 3 (Edn3), tumor growth factor-beta (TGFβ), and growth and differentiation factor 15 (GDF15), all of which have also been linked to myocardial ischemia and infarction(2, 4) (Fig. 1). Cardiac fibroblasts and endothelial cells have been shown to express certain SASP factors including IL-1, IL-6, CXC-chemokine ligand 1 (CXCL1) and CXCL2, TNFα, vascular endothelial growth factor (VEGF), matrix metalloproteinase 1 (MMP1), MMP2, and MMP3, and plasminogen activator inhibitor 1 (PAI1)(12, 20). IL-1, IL-6, and TNFα induce local inflammation in the surrounding cardiac microenvironment(12) and Edn3, GDF15, and TGF-β promote fibrosis and myofibroblast activation in cardiac fibroblasts(4).

Figure 1. Senescent Cells and Their SASP Profiles in the Post Ischemic Heart.

Endothelial cells constitute more than 60% of non-cardiomyocytes, thus playing a pivotal role in maintaining vascular homeostasis and myocardial perfusion. With aging and stress exposure, endothelial cells develop a distinct senescent phenotype characterized by morphological enlargement, flattening, and loss of responsiveness to laminar shear stress, leading to impaired mechanosensation and vascular dysfunction(21). Mechanistically, senescent endothelial cells exhibit enhanced adhesions to the basement membrane, impairing their flow mediated alignment and promoting their persistence within the vascular wall, a process that contributes to vascular inflammation and stiffness(20, 21). Moreover, senescent endothelial cells exhibit a compromised production of endothelial nitric oxide synthase (eNOS) and bioavailability of nitric oxide (NO) contributing to endothelial dysfunction and vascular stiffness(22) (Fig. 1).

Cardiac progenitor cells (CPCs), which make up around 2% of the cardiac cell population, have the unique ability to self-renew and differentiate into various cardiac cell types, thus contributing to cardiac regeneration. However, with aging these progenitor cells can become senescent, losing their ability to maintain homeostasis and their regenerative capacity. This functional decline impairs their ability to repair or regenerate following ischemic injury(23, 24). Senescent CPCs isolated from old (>70 years old) human hearts have higher levels of p16, SA-β-gal, and γH2AX as well as advanced telomere attrition together with a SASP phenotype that entails augmented release of MMP-3, PAI1, IL-6, IL-8, IL-1β, and GM-CSF(23) (Fig. 1).

Furthermore, senescent cardiac immune cells, particularly macrophages and T cells, can develop a chronic low-grade inflammatory profile (“cardiac inflammaging”) that enhances tissue remodeling. With aging, cardiac macrophages lose their phagocytic and reparative functions while acquiring a pro-inflammatory SASP phenotype rich in IL-1β, IL-6, TNF-α, and TGF-β production that drives fibrosis, endothelial injury, and ventricular remodeling(25). Likewise, senescent lymphocytes exhibit clonal expansion and increased IFN-γ production, sustaining chronic inflammation and impairing cardiac regeneration(26).

The accumulation of senescent cells in the heart and the secretion of pro-inflammatory and profibrotic factors thus impair cardiac capacity to maintain tissue homeostasis, limiting capacity for repair subsequent to ischemic injury. Cellular senescence can therefore play a critical role in contributing to the pathogenesis of age-, metabolic-, radiation-, infection-, autoimmune-, and chemotherapy-related cardiac diseases as well as in other conditions associated with increased senescent cell burden.

Ischemia-Reperfusion Injury Following Myocardial Infarction Induces Senescence

Following myocardial infarction, cardiac ischemia-reperfusion injury serves as a critical driver of senescence induction. Key components of IRI include the excessive generation of reactive oxygen species (ROS), DNA damage, mitochondrial dysfunction, and excessive inflammation(2). These factors collectively contribute to the induction of cellular senescence in both cardiomyocytes and interstitial cell populations within the heart. Several studies have since explored the upstream signaling pathways that mediate senescence in the context of MI(2, 7, 13, 14, 27–35).

In both, mouse and rat models of myocardial infarction, ligature of the left anterior descending artery (LAD) followed by reperfusion leads to a progressive increase of senescence markers including SA-β-gal (Senescence-Associated β-Galactosidase), p53, and p16(2, 36). These events are accompanied by the secretion of pro-inflammatory and pro-fibrotic cytokines including interferon gamma-induced protein 10 (IP-10), TGF-β3, interleukin-11 (IL-11), Cdkn1a, Cdkn2a, and fractalkine(2, 36) (Fig. 2a). Notably, cellular senescence is not only observed in cardiomyocytes but also in other interstitial cell populations(2).

Figure 2.: Different Pathways of Senescence Induction Following Myocardial Infarction (MI).

a Autocrine signaling perpetuates senescence in surrounding cells by releasing SASP factors. b Oxidative stress following ischemic injury triggers the formation of Telomere-Associated Foci (TAF) and induces telomere dysfunction. c Drp1 (dynamin-related protein 1) activation in response to ischemia-reperfusion leads to mitochondrial fragmentation. d Following ischemic injury, the stress kinase p38MAPK pathway is activated, leading to an increase in nuclear factor-κB (NF-κB) activity, inducing the expression of SASP factors. e The augmented expression of the transcription factor GATA4 in response to DNA damage enhances production of the senescence-associated secretory phenotype (SASP) factors. f MicroRNAs play a key role in regulating cardiac senescence. miR-18a is upregulated following myocardial infarction (MI), inhibiting autophagy and activating the Akt/mTOR pathway, thereby promoting senescence. miR-34a targets the phosphatase-1 nuclear targeting subunit (PNUTS), leading to increased DNA damage and the induction of senescence.

The increase in oxidative stress following ischemia-reperfusion injury has been demonstrated with staining for 4-HNE, a marker of lipid peroxidation detectable in the infarct zone post-injury. Notably, regions with the highest oxidative stress levels also exhibited the greatest burden of cellular senescence(2). Similarly, telomere dysfunction characterized by the presence of telomere-associated DNA damage foci (TAF), a hallmark of senescent cells, is triggered by oxidative stress and has been observed in cardiomyocytes following ischemia-reperfusion (IR) injury(2) (Fig. 2b). Interestingly, telomere dysfunction correlated with increased myocardial scar size and impaired left ventricular function and vascularization.

Mitochondrial dysfunction represents another critical driver of cardiac senescence. Dynamin-related protein 1 (DRP1), regulating mitochondrial fission(37), represents a key player in mitochondrial dysfunction(23). Experimental models of MI have shown that DRP1 activation in response to ischemia-reperfusion leads to mitochondrial fragmentation in parallel to compromised left ventricular function (Fig. 2C). Of note, siRNA-mediated knockdown of DRP1 and the application of the Drp1 inhibitor Mdivi-1 have been shown to prevent cardiomyocyte senescence and mitochondrial dysfunction after hypoxia/reoxygenation with improvement of left ventricular (LV) function and reduced LV end diastolic pressure following IR and cardiac protection(38). Consistent with this, a hypoxia–re-oxygenation in vitro model of myocardial ischaemia in H9c2 cardiomyoblasts demonstrated that inhibition of DRP1 leads to attenuated expression of senescence markers, suggesting that ischaemia-mediated mitochondrial dysfunction may promote cellular senescence(37). Targeting DRP1 may thus represent a potential therapeutic strategy for cardiac IRI initiated senescence.

Of relevance, chronological age has been shown to affect the accumulation of senescent cells post-MI. Experimentally, it has been demonstrated that old mice, both male and female, exhibit elevated levels of senescence markers in infarcted cardiac tissue(6, 23).

Specific molecular pathways that drive senescence following MI have been identified. p38MAPK (mitogen-activated protein kinase) is a stress-activated kinase pathway that regulates cellular responses to ischemic injury. p38MAPK induces the SASP by increasing transcriptional activity of nuclear factor-κB (NF-κB) thereby leading to upregulation of IL6, IL8, MCP 2, MCP 3, GCP-2, and IL-1β(39) (Fig. 2d). In a murine MI model, the NF-κB-driven SASP expression has been linked to augmented myocardial scar size, impaired vascularization, and exacerbated cardiac remodeling(40). Conversely, clearance of senescent cells in this model led to a reduction of CCL22, IL-6, IL-11, IP-10, eotaxin, and fractalkine, suggesting that the SASP contributes to pathological remodeling processes after MI(41, 42).

Inflammatory SASP signaling following MI is accelerated by GATA4 signaling, a transcription factor involved in cardiac development and stress responses(12). In post-infarction hearts, an increase in cardiomyocytes exhibiting damaged DNA has been observed, corresponding to elevated GATA4 expression in the myocardium in proximity to infarct border zones (Fig. 2e). Inhibition of GATA4 using AAV9-Gata4-shRNA, in turn, led to downregulation of SASP factors. These findings collectively indicate that GATA4 is increased at sites of damaged DNA following MI and may play a critical role in activating the SASP post-infarction(12).

Importantly, while many pro-inflammatory and pro-fibrotic mediators are upregulated in the infarcted myocardium, not all of these factors originate from senescent cells. It is therefore important to differentiate between the acute inflammatory response triggered by IR-MI and the consequences of the SASP secreted by senescent cells. Of relevance, IL-1β, TNF-α, and IL-6 are rapidly induced in the infarcted myocardium as a consequence of sterile inflammation. It remains challenging, at this time, to clearly assign the origin of these inflammatory cytokines to either sterile inflammation or senescent cells(43). At the same time, presence of SASP-related factors including MCP-1, IL-8, CCL11, GM-CSF, IGFBP5, MMP-3, and PAI-1 have been documented in both young and old aged mice after MI(44).

While multiple pathways contribute to senescence induction in cardiac tissue following MI, the loss of regenerative capacity in senescent CPCs further exacerbates the heart’s impaired repair following MI(23). In a mouse model of myocardial infarction, transplantation of senescent CPCs resulted in markedly reduced engraftment and survival compared to cycling-competent cells. In comparison to senescent CPCs, Cyclin CPCs significantly improved LV function and reduced fibrosis, mediated predominantly via paracrine mechanisms that stimulated endogenous repair, an observation that has been documented by increased numbers of BrdU-positive cardiomyocytes and capillaries(23). Of note, MI also induced senescence in cardiac stem/progenitor cells (CSCs), evidenced by the presence of p16-positive CSCs in the ischemic myocardium(44).

Emerging evidence points to microRNAs (miRNAs) as key regulators of cardiac senescence with miR-18a being upregulated after MI, linked to increased senescence. Inhibition of miR-18a in hypoxia-exposed cardiomyocytes, in turn, reduced the number of SA-β-gal-positive senescent cells and promoted autophagy, as evidenced by increased levels of Beclin1, LC3-II, and p62, key markers of autophagic activity (Fig. 2f). This suggests that miR-18a not only promotes senescence but also inhibits autophagy, a crucial process for cellular repair and survival. Additionally, downregulation of miR-18a reduced cellular senescence through the inactivation of the Akt/mTOR pathway, a critical intracellular signaling cascade that increases protein synthesis and growth(27, 45). Similarly, levels of miR-34a were elvated in response to MI and this was linked to compromised myocardial function. miR-34a targets the phosphatase-1 nuclear targeting subunit (PNUTS), improving myocardial function by reducing DNA damage and promoting cell survival(28)(Fig. 2f). These findings underscore the potential of targeting miRNAs, including miR-18a and miR-34a, to mitigate the adverse effects of senescence following MI.

Of translational relevance, clinical studies support the concept of senescence induction following myocardial infarction. Clinical post mortem analysis of ischemic heart tissue has indicated significantly increased expression of senescence markers including p16 and SA-β-gal, with higher levels being observed in patients with coronary artery disease. Blood samples from patients with ischemic heart disease show increased levels of SASP-associated chemokines, including CXCL10, CCL20, and CCL22(29). Furthermore, bone marrow (BM)-derived progenitor cells from patients with ischemic heart disease had shorter telomeres, higher levels of senescence markers, and reduced myeloid differentiation capacity, indicating a functional decline in BM-derived progenitor cells in ischemic heart disease(46). In addition, dysfunctional telomeres in cardiomyocytes have been linked to an increased risk of ventricular arrhythmias, highlighting the clinical relevance of senescence in the context of MI(47).

Thus, myocardial injury has been identified as a driver of senescent cell induction through several mechanisms, including oxidative stress, mitochondrial dysfunction, changes in miRNAs, the SASP, and inflammatory pathways, promoting senescent cell accumulation in post-MI hearts (summarized in Table 1).

Table 1.

Causative and Associative Evidence of Cardiac Senescence following MI.

Cell Type	Model	Main Finding	Causative/Associative	Source
Cardiomyocytes	Murine model of MI using LAD ligation	Increase in the senescence markers SA-β-gal, p53, and p16INK4a following MI.	Associative	2, 36
		Upregulation of SASP secretion, including IP-10, TGF-β3, IL-11, Cdkn1a, Cdkn2a, and fractalkine following MI.
		Increase in the senescence marker TAF correlates with increased myocardial scar size and impaired left ventricular function and vascularization following MI.
		Navitoclax eliminates senescent cells and improves cardiac function following MI.	Causative (pharmacological inhibition)
		Drp1-dependent mitochondrial fission associated with myocardial senescence is induced in the peri-infarct region of mouse hearts after MI.	Associative	37, 38
		Cilnidipine improves cardiac function after MI by inhibiting Drp1-mediated myocardial senescence.	Causative (pharmacological inhibition)
		p38MAPK induces the SASP by increasing the transcriptional activity of NF-κB thus leading to an upregulation of IL6, IL8, MCP 2, MCP 3, GCP-2, and IL-1β linked to augmented myocardial scar size, impaired vascularization, and accentuated cardiac remodeling.	Associative	39, 40, 41, 42
		miR-18a upregulation after MI through the activation of Akt/mTOR pathway.	Associative	27, 45
		miR-18a inhibition reduces SA-β-gal-positive senescent cells and activates autophagy, increasing cellular repair and survival.	Causative (miR-18a antagonist)	27
		Following MI, Navitoclax depletes senescent cells in the heart, leading to reduced scar size, increased angiogenesis, and improved cardiac recovery.	Causative (pharmacological inhibition)	6
		Resveratrol suppresses inflammatory SASP cytokines, thereby reducing cell apoptosis in mice heart after MI.	Causative (pharmacological inhibition)	73
		Hemin inhibits SASP factor secretion, exerting cardioprotective effects but also improving cardiac function post-MI.	Causative (pharmacological inhibition)	74
	Postinfarction mouse hearts and ischemic human myocardium	Inhibition of the transcription factor GATA4 using AAV9-Gata4-shRNA led to the downregulation of SASP factors following MI.	Causative (genetic targeting)	12
Heart Tissue	Rat model of MI	Following MI, Fisetin reduced SASP markers, leading to improved cardiac function by reducing atrial inflammation and fibrosis.	Causative (pharmacological inhibition)	70
Cardiac Fibroblasts and Cardiomyocytes	MI mouse model using LAD ligation, ischemic human myocardium	Ischemia-reperfusion injury triggers GATA4 mediated release of the SASP factor CCN1.	Associative	12, 13
Cardiac Fibroblasts	Hypoxia-treated cardiac fibroblasts	The TGF-β/Smad signaling pathway induces senescence through the p53/p21 pathway and enhances the secretion of SASP components such as IL-6, IL-1β, and FGF2.	Associative	51, 52
	MI mouse model using LAD ligation	p53-deficient infarcted mice hearts had fewer senescent fibroblasts.	Causative	5,11
		Ataxia telangiectasia-mutated kinase (ATM) activation in response to DNA damage after MI induces senescence.	Associative	15
Cardiac stem cells	MI mouse model using LAD ligation	MI induces senescence in cardiac stem/progenitor cells (CSCs), evidenced by the presence of p16-positive CSCs in the ischemic myocardium.	Associative	44
Bone marrow derived progenitor cells	Clinical samples of patients with ischemic heart diseases	Telomere shortening and reduced differentiation capacity in ischemic heart disease.	Associative	46

Yin and Yang of Cardiac Senescence: Long-Term Consequences of Myocardial Infarction

Myocardial infarction followed by ischemia reperfusion injury initiates a cascade of adverse processes that may ultimately lead to heart failure with short- and long-term changes in LV size, shape, function, and cellular and molecular composition(48). Infarct healing is initiated with the infiltration of inflammatory cells, activation of matrix metalloproteinases (MMPs), myofibroblast production of extracellular matrix, and scar formation(49). Both clinical and experimental studies have demonstrated aging-associated defects in inflammation, collagen deposition, and cardiac repair, all contributing to adverse remodeling including ventricular dilation and hypertrophy(50).

MI induces senescence in cardiac fibroblasts (CFs), as evidenced by the accumulation of senescent CFs and increased SA-β-gal activity and senescence markers, including p16, p21, and p53 in infarcted mouse hearts after 7 days(5) (Fig. 3a). Similar findings have been observed in hypoxia-treated CFs(5). The TGF-β/Smad signaling pathway, a key driver of post-MI cardiac fibrosis also promotes fibroblast senescence(51). In CFs, TGF-β1 induces senescence through the p53/p21 pathway and enhances the secretion of SASP components such as IL-6, IL-1β, and Fibroblast Growth Factor 2 (FGF2)(52). Additionally, in cardiac myofibroblasts, TGF-β1 induces cell cycle arrest, a feature of senescence, linking fibrosis and senescence(30).

Figure 3. Long-Term Consequences of Cardiac Senescence Following Myocardial Infarction (MI).

a Senescent Fibroblasts after MI. b Anti-Fibrosis effects of Senescent Fibroblasts following MI; c Pro Fibrosis effects of Senescent Fibroblasts as a consequence of MI. d Senescent cardiomyocytes post-MI promoting heart failure.

Beneficial Effects of Senescence and Cardiac Remodeling After MI

An intriguing aspect of current research is the dual role of fibroblast senescence in cardiac fibrosis after MI, with evidence suggesting both protective and deleterious effects. Most recent findings have pointed to a beneficial role of fibroblast senescence in mitigating fibrosis (summarized in Fig. 3b). Overexpression of the senescence marker p16 immediately following myocardial injury through adenoviral delivery improved cardiac function and reduced the fibrotic area post-MI. Conversely, p16 knockdown diminished these protective effects, underscoring the role of senescent cells in modulating the fibrotic response(31). Similarly, p53-deficient infarcted mice hearts exhibited fewer senescent fibroblasts but had heightened fibrosis and collagen deposition, further suggesting that fibroblast senescence serves as a physiological mechanism, limiting fibrosis after MI(5, 11).

In support of these findings, studies investigating Ataxia Telangiectasia-Mutated kinase (ATM) demonstrated a key role linking senescence to cardiac fibrosis. ATM activation in response to DNA damage induces senescence, particularly in cardiac fibroblasts, limiting excessive collagen deposition while promoting angiogenesis through the SASP, thus protecting against post-MI heart failure(15). Conversely, ATM deficiency exacerbates cardiac remodeling and dysfunction. Post-MI, experimental ATM deficiency led to increased apoptosis and fibrosis, contributing to adverse early remodeling(32). Long-term, mice had compromised left ventricular function, including increased end-systolic volume, reduced ejection fraction, greater myocyte hypertrophy, and more extensive fibrosis, despite comparable infarct sizes. These findings collectively highlight the complex, context-dependent role of fibroblast senescence in post-MI remodeling and cardiac function(33).

Cardiomyocyte senescence, alongside fibroblast senescence, exerts antifibrotic effects through the GATA4-CCN1 pathway after myocardial infarction. Ischemia-reperfusion injury triggers GATA4 mediated release of the SASP factor CCN1 (Cellular Communication Network Factor 1), acting in an autocrine fashion within cardiomyocytes and fibroblasts to promote cardioprotection and regulate fibrosis(12, 13). In turn, inhibition of GATA4 using AAV9-Gata4-shRNA led to increased collagen production (60% to 80%) and worsened cardiac function, including impaired ejection fraction, LV posterior wall thinning, and LV dilatation(12).

Additionally, in vitro and in vivo studies have shown that senescent cardiac fibroblasts (CF) inhibit the proliferation of neighboring non-senescent CFs, slowing progression of fibrosis(13). Moreover, senescent fibroblasts have compromised responsiveness to TGF-β1 signaling. For instance, palmitate-induced senescent CFs exhibited lower levels of collagen I and III, MMP-2, α-SMA mRNA, and impaired collagen gel contraction. These findings suggest that senescence prevents fibroblast differentiation, limiting their role in fibrosis(34). Building on this background, TGF-β-induced senescence, combined with the reduced responsiveness of senescent cells, may act as a self-regulatory mechanism limiting excessive fibrosis during acute injury.

In line with these observations, experimental models have shown that the extent of fibrosis differed after infarction between young and old hearts despite similar TGF-β levels(14). The age difference was linked to Smad2 phosphorylation, activating the fibrogenic pathway responsible for collagen production. In young mice, strong Smad2 phosphorylation in response to TGF-β1 promoted fibrosis(53). In contrast, fibroblasts derived from older, senescent myocardium underwent less Smad2 phosphorylation following TGF-β1 stimulation, suggesting that senescence impairs fibrogenic signaling and consequently limits fibrosis.

Detrimental Effects of Senescence on Cardiac Remodeling After MI

While many studies highlight the beneficial effects of senescence in mitigating cardiac fibrosis, there is also evidence suggesting its harmful effects on cardiac remodeling. Notably, several studies have shown that depleting senescent cells with senolytics leads to improvements in cardiac function and remodeling(2, 36, 44)(summarized in Fig. 3c).

In older mice, senescence is linked to defective reparative fibrosis of the infarcted myocardium, accompanied by reduced collagen deposition in the scar tissue in ischemic hearts(14). In studies in old mice treated intermittently with each of several different senolytics, agents that selectively eliminate senescent cells resulted in decreased senescent cells in the heart in vivo in parallel to an ameliorated cardiac fibrosis and improved ejection fraction and function (20, 23). Selective removal of highly p16^Ink4a-expressing cells, many of which are senecent, from aged transgenic INK-ATTAC mice confirmed those data. Moreover, senescent fibroblasts release proinflammatory SASP factors causing tissue damage and long term remodeling(11, 15). Furthermore, a variety of miRNAs, including miR-15, miR-17, miR-22, miR-34a, and miR-1468–3p have been implicated in fibroblast senescence and the regulation of post-ischemic cardiac fibrosis(53–56). These miRNAs exhibit profibrotic properties and are associated with several cardiac conditions including heart failure (HF) and atrial fibrillation(57, 58). For example miR-22 and miR-21 can be upregulated in the aging and infarcted heart, promoting fibroblast activation and adverse remodeling(55, 59). Members of the miR-29 family (miR-29a, miR-29c) and miR-34a have been shown to drive fibrosis and senescence through TGF-β1/Smad4-dependent pathways, while inhibition of these miRNAs reduces infarct size and apoptosis(56, 60). Conversely, miR-17–3p ameliorates fibroblast senescence by targeting Par4/FAK signaling, thereby mitigating post-ischemic remodeling(54, 61).

Despite these insights, the role of senescence in post-ischemic cardiac fibrosis after MI remains complex and requires further investigation.

Hypertrophic Remodeling and Heart Failure After Myocardial Infarction

Structural remodeling after MI is characterized by fibrosis and cardiomyocyte hypertrophy, ultimately contributing to the development of heart failure (HF). Experimental MI models have provided insights into the role of accumulated senescent cells following ischemia-reperfusion injury. Experimental models are also valuable tools in investigating long-term consequences of MI. Four weeks post-injury, cardiomyocytes in the infarct border zone exhibit fibrotic and hypertrophic changes, evidenced by increased expression of stress and hypertrophy markers including Myh7, Acta1, Nppa, Mybpc2, and Capn3. Notably, treatment with senolytic agents has been shown to reduce these markers, suggesting that clearing senescent cells can mitigate cardiomyocyte hypertrophy while improving cardiac function(44). In other MI mouse models, reactive oxygen species (ROS)-dependent electrophiles including 8-nitroguanosine-3′5′-cyclic monophosphate (8-NO₂-cGMP) have been shown to mediate myocardial senescence through H-Ras signaling during late-stage heart failure following MI(62) (Fig. 3d). Together, these findings suggest a role for cardiomyocyte senescence in driving maladaptive hypertrophic remodeling and progressive heart failure after MI.

Therapeutic Approaches Targeting Cardiac Senescence After MI

Improved understanding of mechanisms driving cellular senescence following ischemia reperfusion injury after myocardiaI infarction may point to novel therapeutic options. Since targeting cardiac IRI has been investigated as a promising approach for blocking inflammatory signaling following MI, inhibiting cellular senescence induction may further improve clinical outcomes and delay, prevent, or alleviate adverse-side effects in the long term.

Senotherapeutics

Senotherapeutics include drugs that either eliminate senescent cells (senolytics) or reprogramme senescent cells and suppress the SASP (senomorphics). Senolytics selectively induce cell death in senescent cells, effectively eliminating them. Notably, a broad range of senolytics has already been tested for cardiovascular disease with several studies directly focusing on MI. The senolytic agents Dasatinib (D) and Quercetin (Q) have already been tested in aged mice, where they alleviated impaired ejection fraction(20), activating resident cardiac progenitor cells (CPCs)(20, 44), reduced myocardial hypertrophy and fibrosis(44), prolonged the survival of cardiac allografts(35), and increased proliferative cardiomyocytes(23). Following MI in mice, D+Q treatment enhanced left ventricular function (Fig. 4a) and cleared senescent CPCs, restoring the proliferative and differentiation capacities of healthy CPCs(44). However, it should be noted that long term continuous administration of D for months to years as used for treating patients with leukemias or lyphomas (as opposed to the intermittent, 1 to 4 days/month treatment regimens shown effective at reducing senescent cell burden in early clinical trials may also cause cardiac dysfunction and heart failure after several months, possibly due to the death of non-senescent cardiomyocytes(63). Coronary microvascular dysfunction (CMD) is an early functional feature of coronary vascular aging and increased atherosclerotic cardiovascular disease risk. Circulating levels of the geroprotective factor, α-Klotho, were lower in patients with CMD than in patients without CMD as noted during invasive coronary microvascular and endothelial function testing for chest pain(64). Interestingly, in another clinical trial in patients with idiopathic pulmonary fibrosis, urinary α-Klotho was increased in each of 20 subjects after a brief oral treatment with D+Q(65). Thus, a safety study of intermittent oral D+Q in patients for patients suffering from ischemia-induced myocardial injury could be enlightening while enabling an efficacy study examining the impact of D+Q on cardiac function.

Figure 4. Therapeutic Approaches Targeting Cardiac Senescence after Myocardial Infarction (MI).

a Dasatinib + Quercetin (D+Q) reduce senescence by inhibiting SCAP through PI3K/Akt signaling. b Navitoclax, a BCL-2 family inhibitor, induces apoptosis of senescent cells by targeting Senescent Cell Anti-apoptotic Pathways (SCAP). c Fisetin reduces SASP secretion through modulation of the p38MAPK/NF-κB pathway. d Resveratrol suppresses SASP expression through sirtuin 1. e Hemin upregulates the anti-inflammatory enzyme HO-1 thus decreasing SASP secretion. f Cilnidipine inhibits mitochondrial fission and prevents senescence. g+h Levosimendan and Losartan reduce senescent cell populations by downregulating p16 expression. i Metformin reduces SASP levels by activating the AMPK pathway. j Growth differentiation factor 11 (GDF11) inhibits the senescence marker p16, facilitating the clearance of senescent cells in a manner similar to senolytics, promoting the rejuvenation of cardiac stem cell populations. k Activation of AMPK, AKT/mTOR, and WNT pathways enhance stem cell regeneration and proliferation.

Navitoclax, a BCL-2 inhibitor (Fig. 4b) has shown similar benefits in rodent MI models, improving ejection fraction, cardiac output, and stroke volume(6). By depleting senescent cells, Navitoclax reduced p21 expression, telomere-associated DNA damage, and SASP levels, including IL-11(66), IL-16(67), CCL22(29), MIP-3β, and fractalkine (CX3CL1)—all of which are linked to cardiac fibrosis and worse outcomes in MI patients- thus leading to reduced scar size, increased angiogenesis, and improved cardiac recovery. Pre-treatment with Navitoclax before MI induction also enhanced survival and cardiac performance.

To mitigate some of the systemic toxicities observed in cancer trials including severe and unpredictable neutropenia and thromocytopenia(68), delivery of Navitoclax by poly (lactic-co-glycolic acid) PLGA nanoparticles has been developed(36). This approach successfully eliminated senescent cells in ischemia-reperfusion injury models, reduced inflammation and fibrosis, and improved cardiac function, apparently without systemic side effects(36). Navitoclax-eluting stents have also shown promise in reducing vascular smooth muscle cell senescence and restenosis in a rabbit model(69).

The natural flavonoid fisetin exerting senolytic and senomorphic properties (inhibition of the SASP), has demonstrated potential in improving post-MI cardiac remodeling and function by reducing SASP markers, including IL-1β and TNF-α(70) (Fig. 4c). In a rat model of MI, fisetin improved cardiac function by reducing atrial inflammation and fibrosis and the susceptibility to atrial fibrillation (AF), while enhancing left atrial (LA) expansion. These effects were mediated through the p38MAPK/NF-κB and TGF-β/Smad3 pathways, both critical regulators of cardiac fibrosis(70, 71). Additionally, fisetin demonstrated protective effects against cardiac hypertrophy by suppressing the MAPK signaling pathway in a cardiomyocyte hypertrophy model(72).

Resveratrol, an agonist of sirtuin 1 (Sirt1), appears to have capacity to suppress inflammatory cytokines associated with the senescence-associated secretory phenotype (SASP), including IL-18, IL-1β, IL-6, and TNF-α, while also reducing cell apoptosis in mouse hearts following MI (Fig. 4d). These findings highlight Reservatol’s potential to mitigate ischemia-reperfusion (IR)-induced cellular senescence(73). Similarly, treatment with Hemin, an agent known to upregulate the anti-oxidative and anti-inflammatory enzyme heme oxygenase-1 (HO-1), significantly inhibited SASP factors such as IL-1, IL-6, and TNF-α (Fig. 4c). This intervention not only exerted cardioprotective effects but also improved cardiac function post-MI(74).

Collectively, senotherapeutic agents hold great promise as a next-generation therapy for myocardial injury, improving cardiac function following myocardial infarction by clearing senescent cells. While these findings point to the possible therapeutic efficiacy of senotherapies, potential side effects need to be considered. With the possibly protective role of myocardial fibrosis and scar formation in maintaining ventricular integrity(75), excessive removal of senescent myofibroblasts or cardiomyocytes could, at least in theory, impair scar formation and increase susceptibility to cardiac rupture. Of additional relevance, senescent cells also have anti-tumor effects by limiting the proliferation of damaged cells and promoting immune-mediated clearance of pre-malignant clones(76). Thus, interfering with the capacity to generate senescent cells in response to cancerous mutations may compromise tumor surveillance and potentially increase oncogenic risk. However, senolytics do not interfere with senescent cell generation. Rather, they remove persisting, pro-inflammatory senescent cells that potentially harbour cancerous mutations, which has led to clinical trials alternating senolytics with radiation and chemotherapy for treating cancers(77, 78). Moreover, the off-target effects of senolytics on non-senescent cells must be carefully considered. For instance, Navitoclax, a BCL-2 inhibitor, has been associated with dose-limiting thrombocytopenia due to BCL-xL inhibition in platelets(79). Thus, despite the promising results observed with senotherapeutic approaches following myocardial infarction, their potential off-target and systemic effects warrant caution and patients should not be treated with these agents unless clinical trials demonstrate their safety, tolerability, target engagement, and effectiveness.

Conventional Drug Therapies

Numerous clinically approved treatments for cardiovascular disease have been found to exhibit anti-senescence effects upon further investigation(37, 80). The Ca2+ Channel blocker Cilnidipine has been shown to significantly improve cardiac function after MI by inhibiting Drp1-mediated myocardial senescence, evident by decreased Drp1 activity and SA-b-gal–positive areas in the peri-infarct zone of the LV myocardium(22, 37, 38) (Fig. 4f). The experimental treatment with Cilnidipine early after MI has been shown to significantly protect LV function while reducing LV hypertrophy and remodeling(37).

The calcium sensitizer levosimendan improved cardiac function in a rat MI model by reducing senescence-associated p16 expression in cardiomyocytes (Fig. 4g) alongside decreased myocardial ANP, inflammatory IL-6, and fibrogenic CTGF mRNA levels, thereby attenuating the inflammatory response(80). Similarly, the angiotensin II-receptor blocker losartan has been reported to partially reverse left ventricular dysfunction and remodeling after MI in rats, while also reducing oxidative senescence markers such as p16 expression in cardiomyocytes(22, 81) (Fig. 4h). Notably, clinical trials have shown that AT1 blockers improve survival and EF in heart failure and post-MI patients, with their impact on senescence potentially contributing to these therapeutic benefits(82).

The antidiabetic agent metformin has been shown to inhibit the release of pro-inflammatory SASP factors, including IL-1β, IL-18, and TNF-α, through AMPK activation (Fig. 4i), which subsequently suppressed NLRP3 inflammasome activity. In a rat model of MI, metformin treatment reduced ischemia/reperfusion (I/R) injury, significantly decreased myocardial infarct size, and attenuated myocardial fibrosis(83). Of particular interest is the reduction in cardiovascular morbidity in patients taking SGLT-2 antagonists for diabetes(84). These agents are effectively senolytic: they disable some of the defenses persisting senescent cells use to avoid clearance by the immune system(85). Nevertheless, it is important to clarify that some observed effects on cellular may be indirect, mediated through the improvement of underlying systemic conditions rather than direct modulation of senescence pathways within the cardiac tissue. Drugs including Cilnipine and metformin affecting hyepertension and glycemic control may reduce cellular stressors including oxidative stress(86), inflammation(87), and metabolic dysfunction(88), all potentially driving senescence(89). Thus, the reduction in senescence markers observed subsequent to the application of these agents may partly reflect an improved systemic disease control rather than a direct senescence-targeting activity.

Stem Cell Therapy

Stem cell senescence is a critical factor in the limited regenerative capacity of the heart following ischemic injury, particularly in older individuals(23, 24). Ischemic cardiac injury remains a major contributor to heart failure, underscoring the need for strategies that interfere with senescence, promoting tissue repair. Growth differentiation factor 11 (GDF11), a member of the activin-transforming growth factor β superfamily, has shown significant potential in rejuvenating stem cell activity and enhancing tissue repair after ischemia/reperfusion injury. Utilizing targeted microbubble destruction (UTMD) for GDF11 overexpression, studies have demonstrated improved cardiac function, reduced infarct size, diminished senescence markers (p16, p53), and increased proliferation of cardiac stem cells (Sca-1+) as well as enhanced angiogenesis(90) (Fig. 4j).

Key molecular pathways linked to senescence, including AMP-activated protein kinase (AMPK), Wingless-related integration site (WNT) and AKT-mechanistic target of rapamycin (AKT–mTOR), play critical roles in cardiac repair. Activation of AMPK improves the reparative capacity of senescent mesenchymal stem cells (MSCs) and cardiac progenitor cells (CPCs), reducing fibrosis and enhancing cardiac function(91). Similarly, modulation of the WNT pathway (e.g., WNT3A overexpression) and insulin-like growth factor 1 (IGF1)/SIRT1 activation delays senescence and increases MSC proliferation, boosting their regenerative capacity in mouse MI models(92) (Fig. 4k).

Notably, the clearance of senescent cells through senolytics increases resident CPCs and cardiomyocyte proliferation (e.g., Ki67+, EdU+), rejuvenating stem cell populations to repair damaged tissue(23). This highlights the complementary roles of senescent cell clearance and regeneration: rescuing reversible cells and targeting irreversibly senescent cells for removal. Stem cell-based strategies could therefore enhance the therapeutic potential of senolytics in heart repair and regeneration following ischemic injury. Despite significant progress in stem cell rejuvenation and molecular modulation strategies, the functional efficacy of cardiac progenitor cells (CPCs) in post-myocardial infarction repair remains controversial. Cardiac repair is likely mediated predominantly through paracrine mechanisms rather than through direct differentiation and structural integration of transplanted CPCs(23). With persisting safety concerns, incomplete differentiation of progenitor cells carries a potential risk of tumorigenesis with the activation of oncogenic pathways(93). Furthermore, immature or improperly integrated cells may interfere with cardiac electrophysiology, thereby predisposing to arrhythmias(94). These challenges emphasize the need for further optimization of CPC differentiation protocols and thorough evaluation of long-term safety to realize the full therapeutic potential of stem cell-based cardiac repair.

Future Directions and Outlook

The latest advances in senescence-targeting strategies for MI have generated significant interest as demonstrated by the growing number of preclinical studies. However, clinical trials specifically assessing senolytics in cardiovascular diseases remain rare (Fig. 5). To move these therapies toward clinical application, it is crucial to prioritize studies that investigate the safety and efficacy of established senolytics in cardiovascular diseases. Encouragingly, recent phase 1 trials in Alzheimer’s disease(95) and idiopathic pulmonary fibrosis(96), demonstrated safety, feasibility, and tolerability of the senolytic combination dasatinib and quercetin (D+Q). Interestingly, Quercetin alone has been tested in a phase 2 clinical trial evaluating its effects in Coronary Artery Bypass Surgery (Q-CABG)(97) as well as in another trial investigating its impact on cardiometabolic outcomes(98), offering hope for similar applications in cardiac diseases, including MI. A near-term translational step would be a small, mechanistically focused trial in older patients (>60 years) with a first MI after revascularization, randomized to GDMT plus senolytics versus GDMT plus placebo. This population is expected to carry an increased senescent burden, making them suitable for initial testing. Based on preclinical evidence that Dasatinib + Quercetin (D+Q) efficiently clears senescent cardiac cells and improves remodeling in aged mice(23), D+Q would be the most appropriate first candidates. Primary outcomes may include changes in LV remodeling at baseline and 6 months while changes of circulating SASP factors could be assessed. Recognizing the invasive approach, endomyocardial biopsies may provide information on the kinetics of senescent cell markers including p16, p21, and γH2AX.

Figure 5. Future Perspectives in Research Into Relationships Between Cellular Senescence and Myocardial Infarction.

Future work is necessary for improving our understanding of the mechanisms driving senescence after MI (Fig. 5). Identifying how senescent fibroblasts contribute to cardiac remodeling and determining whether their effects are context- or time-dependent could help optimize therapeutic strategies. For example, the timing of senolytic administration may play a critical role in distinguishing beneficial versus detrimental effects of senescence post-MI. Additionally, exploring senomorphic agents that specifically attenuate the inflammatory and fibrotic impact of the SASP could offer complementary therapeutic benefits (Fig. 5). In addition to pharmacological strategies, investigating how current clinical treatments impact cardiac senescence is of interest. Typically, if hypotension and insufficient tissue perfusion persist despite initial rapid reperfusion therapy, temporary mechanical circulatory support (t-MCS), e.g., with Impella devices, is indicated(99).

These devices have demonstrated reverse remodeling, improving long-term cardiac function(100). The underling mechanism driving cardiac recovery and impeding chronic heart failure, however, remain unknown. Investigating whether t-MCS may affect the induction of senescence or impact senescence-related pathways would be of significant interest to provide mechanistic insights (Fig. 5).

Although this field is still emerging, targeting senescent cells bears the potential for improving outcomes and quality of life in patients with myocardial injury. Bridging the gap between preclinical findings and clinical application will require collaborative and interdisciplinary efforts to refine these innovative therapies.

Conclusions

Cardiac senescence is increasingly recognized as a critical factor in the progression of many cardiovascular diseases, reshaping the characteristics and functionality of cardiac cell populations. The induction of senescence following ischemic myocardial injury has been well-documented, with senescent cell accumulation impairing cardiac function, driving inflammation and adverse remodeling, and ultimately resulting in fibrosis and heart failure. Targeting senescent cells or intervening in the upstream processes that trigger their formation presents a transformative opportunity to enhance post-myocardial recovery and long-term outcomes. Moving forward, translating these therapeutic approaches into clinical practice is essential to addressing the unmet needs of patients with CVDs, paving the way for innovative strategies to combat myocardial infarction and its long-term complications.