Senescence and aging. Aging is characterized by senescent cell accumulation into the body. Senescence can be achieved replicatively or induced by stress. Once activated, the p16 and p53/p21 pathways converge with each other, regulating the Rb mechanism, leading to cell cycle arrest, and consequently, the senescence. This results in the release of cytokines and chemokines, driving towards a systemic inflammatory condition that lead to aging and age-related diseases. The senescent cells are characterized by a high lysosomal β-galactosidase activity and, in association with others characteristic factors, consist the gold standard for the senescence characterization.