Figure 1. The onset of cellular senescence in normal tissue takes place in response to different stimuli (1). Some SASP factors are involved in immune cell recruitment, which act in the clearance of the senescent cells (2). Then, to restore the normal tissue, a regeneration process is necessary (3, 4). When a combination of persistent damage and immune system decay occurs, senescent cells accumulate, creating a pro-inflammatory and pro-tumorigenic environment and fibrotic tissue. Over time, this leads to disease, such as cancer progression, insulin resistance, osteoarthritis, atherosclerosis, and brain pathologies, among others (5, 6).