Senescent Cells Contribute to Damage and Dysfunction Following a Heart Attack
Senescent cells are involved in tissue regeneration. Cells enter a senescent state following injury, and in the usual course of events assist in the intricate coordination between immune cells, stem cells, and other cell types that is required to regrow tissue. These senescent cells are then cleared by the immune system. With age, in poorly regenerative tissues, or in severe or persistent injuries, the presence of senescent cells following injury can become excessive and maladaptive. The signaling produced by senescent cells lasts too long, the cells are not cleared, and it causes further harm. As researchers here note, this is what happens following a heart attack, suggesting that there is likely some timing for the delivery of senolytic therapies to selectively destroy the cells become senescent immediately following the ischemic injury of a heart attack that could improve patient outcomes.
Currently, the primary causes of death following myocardial infarction include sudden cardiac death, malignant arrhythmias, and acute heart failure, all resulting from myocardial necrosis caused by coronary artery occlusion. Cellular senescence refers to the permanent arrest of cell proliferation in response to stress stimuli; it serves as a crucial tumor defense mechanism and is closely associated with tissue aging and chronic inflammation. The senescence-associated secretory phenotype (SASP) is one of the most characteristic features of senescent cells. Cardiac cells develop a SASP and secrete SASP factors in response to stimuli such as oxidative stress, DNA damage, and hypoxia, playing a key role in immune regulation and tissue repair following myocardial infarction.
The SASP exhibits marked spatiotemporal heterogeneity following myocardial infarction: during the acute phase, it contributes to inflammatory amplification and immune cell recruitment; during the subacute phase, it is involved in inflammation resolution, matrix remodeling, and scar formation; and during the chronic phase, it promotes chronic inflammation, paracrine senescence, pathological fibrosis, and cardiac dysfunction. Spatially, the SASP influences scar stabilization in the infarct zone, inflammation-electrophysiological coupling in the border zone, and compensatory remodeling in the distal region. The sustained expression of the SASP is a major driver of adverse ventricular remodeling and excessive fibrosis following myocardial infarction.
Therefore, targeting senescent cells and persistent, pathological SASP represents a highly promising therapeutic strategy in the field of cardiovascular regenerative medicine. This review will discuss senescence in different cell types following myocardial infarction, the spatiotemporal heterogeneity of the immune response mediated by the SASP after myocardial infarction, and the immune cells regulated by the SASP.