Aging leads to progressive organ dysfunction, and many chronic degenerative diseases are characterized by accelerated aging of organs and apparatus. Thus, disentangling the effects of aging and age-related diseases is extremely difficult. For instance, according to the Global Burden of Disease Study, the prevalence of ischemic heart disease is 15 % in the 65-69 years age group, 19 % in the 70-74 years age group, and 26 % in those with 75+ years of age; the corresponding figures for chronic obstructive pulmonary disease (COPD) are 10 %, 14 %, and 24 %. This strong association with age reflects both the cumulative exposure to risk factors and the impact of age itself. A fundamental mechanism of the latter effect is the accumulation of senescent cells, i.e., cells that are still viable but are in an irreversible cell cycle arrest, which are not only dysfunctional, but also produce a wide array of substances (cytokines, chemokines, proteases, etc.) – the senescent-associated secretory phenotype (SASP) – that in turn induce cell cycle arrest and senescence in other cells.
1. Yousefzadeh, M.J. ∙ Flores, R.R. ∙ Zhu, Y. ...
