Aging is a major risk factor for cardiovascular disease. Although the impact of aging has been extensively studied, little is known regarding the aging processes in cells of the heart. Here we analyzed the transcriptomes of hearts of 12-week-old and 18-month-old mice by single-nucleus RNA-sequencing. Among all cell types, aged fibroblasts showed most significant differential gene expression, increased RNA dynamics, and network entropy. Aged fibroblasts exhibited significantly changed expression patterns of inflammatory, extracellular matrix organization angiogenesis, and osteogenic genes. Functional analyses indicated deterioration of paracrine signatures between fibroblasts and endothelial cells in old hearts. Aged heart-derived fibroblasts had impaired endothelial cell angiogenesis and autophagy and augmented proinflammatory response. In particular, expression of Serpine1 and Serpine2 were significantly increased and secreted by old fibroblasts to exert antiangiogenic effects on endothelial cells, an effect that could be significantly prevented by using neutralizing antibodies. Moreover, we found an enlarged subpopulation of aged fibroblasts expressing osteoblast genes in the epicardial layer associated with increased calcification. Taken together this study provides system-wide insights and identifies molecular changes of aging cardiac fibroblasts, which may contribute to declined heart function.

Aging is a major risk factor for impaired cardiovascular health. Because the aging myocardium is characterized by microcirculatory dysfunction, and because nerves align with vessels, we assessed the impact of aging on the cardiac neurovascular interface. We report that aging reduces nerve density in the ventricle and dysregulates vascular-derived neuroregulatory genes. Aging down-regulates microRNA 145 (miR-145) and derepresses the neurorepulsive factor semaphorin-3A. miR-145 deletion, which increased Sema3a expression or endothelial Sema3a overexpression, reduced axon density, mimicking the aged-heart phenotype. Removal of senescent cells, which accumulated with chronological age in parallel to the decline in nerve density, rescued age-induced denervation, reversed Sema3a expression, preserved heart rate patterns, and reduced electrical instability. These data suggest that senescence-mediated regulation of nerve density contributes to age-associated cardiac dysfunction.

BACKGROUND: Aging is a major, yet unmodifiable, cardiovascular risk factor and is associated with vascular alterations, increased cardiac fibrosis, and inflammation, all of which contribute to impaired cardiac function. However, the microenvironment inciting age-related alterations within the multicellular architecture of the cardiac tissue is unknown. METHODS: We investigated local microenvironments in aged mice hearts by applying an integrative approach combining single-nucleus RNA sequencing and spatial transcriptomics of 3- and 18-month-old mice. We defined distinct cardiac niches and studied changes in their cellular composition and functional characteristics. We treated mice with broad-spectrum senolytics dasatinib and quercetin, and endothelial-specific senolytic fisetin and studied their effects on senescence and macrophage populations. RESULTS: Integration of spatial transcriptomics data across 3- and 18-month-old hearts allowed the identification of 11 cardiac niches, which were characterized by distinct cellular composition and functional signatures. Aging did not alter the overall proportions of cardiac niches but led to distinct regional changes, particularly in the left ventricle. While cardiomyocyte-enriched niches showed disrupted circadian clock gene expression, vascular niches showed major changes in proinflammatory and profibrotic signatures and altered cellular composition. We particularly identified larger vessel–associated cellular niches as key hotspots for activated fibroblasts and bone marrow–derived Lyve1 ⁻ (lymphatic vessel endothelial hyaluronan receptor 1) and resident Lyve1 ⁺ macrophages in aged hearts, with interactions of both cell types through the C3:C3ar1 (complement C3 and Complement C3a receptor 1) axis. These niches were also enriched in senescent cells exhibiting high expression of immune evasion mechanisms that may impair senescent cell clearance. Removal of senescent cells by senolytics reduced the presence of Lyve1 ⁻ macrophages. CONCLUSIONS: Our findings indicate that the perivascular microenvironment is particularly susceptible to age-related changes and serves as a primary site for inflammation-driven aging, so-called inflammaging. This study provides new insights into how aging reshapes cardiac cellular architecture, highlighting vessel-associated niches as potential therapeutic targets for age-related cardiac dysfunction.

Aging is the most important yet unmodifiable risk factor for cardiovascular disease (CVD). As a result, targeting cardiovascular aging has emerged as a promising strategy to promote long‐term cardiovascular health. This review summarizes current knowledge on the effects of aging within the cardiovascular system as well as systemic processes that modulate them. We highlight the roles of cellular senescence and the senescence‐associated secretory phenotype (SASP), emphasizing their heterogeneous contributions to chronic low‐grade inflammation and tissue remodeling—collectively termed inflammaging. Advances in biomarkers, animal models, and systems biology approaches have deepened our understanding of the interplay between senescence, inflammaging, and cardiovascular dysfunction, including the pivotal role of macrophages in senescent cell clearance. Therapeutic strategies are diverse, ranging from senolytic approaches designed to selectively eliminate senescent cells, to SASP modulation, and interventions targeting chronic inflammation and metabolic dysregulation. Of particular interest, drugs already in clinical use—such as metformin and other anti‐diabetic agents—show beneficial effects on aging‐related pathways, suggesting that their cardiovascular protection may in part reflect anti‐aging properties. Despite these advances, therapies directly targeting senescence and inflammaging to reduce the global burden of CVD remain an urgent unmet need.

Aims: Members of the VEGF family are crucial modulators of vascular and neural function. While VEGFA signalling has been shown to mitigate several aging-related cardiac phenotypes and prolong survival in aged mice, the role of VEGFB in cardiac aging remains underexplored. In this study, we identify a significant decline in Vegfb expression, particularly of its soluble isoform Vegfb186, in aged mouse and human hearts. To assess the therapeutic potential of VEGFB in aging-associated cardiac pathologies, we used AAV9-mediated gene transfer to overexpress Vegfb186 in 18-month-old male C57Bl/6J mice. Methods and results: VEGFB is known to exhibit vascular and neuroprotective effects that we assessed in the ageing heart. In the aged heart, doses of Vegfb186 overexpression that had only a modest effect on the vascular endothelium prevented age-induced diastolic dysfunction and fibrosis. Vegfb186 treatment additionally restored sympathetic and sensory nerve fibre density and increased heart rate variability. Although Vegfb186 overexpression induced cardiac hypertrophy, our findings indicated that this hypertrophy was compensatory rather than pathological as Vegfb186 overexpression corrected the elevated cardiomyocyte length-to-width ratio observed in aged hearts, a metric typically indicative of pathological remodelling. Cardiac single-nucleus RNA sequencing of the hearts and in vitro analysis of the cardiomyocytes indicated up-regulation of the STAT3 signal transduction pathway as a potential contributor of VEGFB-induced cardiac hypertrophy. Conclusion: Our findings demonstrate that Vegfb186 overexpression partially reverses age-related cardiac pathologies such as diastolic dysfunction and fibrosis. This work highlights VEGFB as a potential therapeutic target for combating cardiac aging and its associated dysfunctions.

The coronavirus SARS-CoV-2 is the cause of the ongoing COVID-19 pandemic. Most SARS-CoV-2 infections are mild or even asymptomatic. However, a small fraction of infected individuals develops severe, life-threatening disease, which is caused by an uncontrolled immune response resulting in hyperinflammation. However, the factors predisposing individuals to severe disease remain poorly understood. Here, we show that levels of CD47, which is known to mediate immune escape in cancer and virus-infected cells, are elevated in SARS-CoV-2-infected Caco-2 cells, Calu-3 cells, and air−liquid interface cultures of primary human bronchial epithelial cells. Moreover, SARS-CoV-2 infection increases SIRPalpha levels, the binding partner of CD47, on primary human monocytes. Systematic literature searches further indicated that known risk factors such as older age and diabetes are associated with increased CD47 levels. High CD47 levels contribute to vascular disease, vasoconstriction, and hypertension, conditions that may predispose SARS-CoV-2-infected individuals to COVID-19-related complications such as pulmonary hypertension, lung fibrosis, myocardial injury, stroke, and acute kidney injury. Hence, age-related and virus-induced CD47 expression is a candidate mechanism potentially contributing to severe COVID-19, as well as a therapeutic target, which may be addressed by antibodies and small molecules. Further research will be needed to investigate the potential involvement of CD47 and SIRPalpha in COVID-19 pathology. Our data should encourage other research groups to consider the potential relevance of the CD47/ SIRPalpha axis in their COVID-19 research.