Senescence: No country for old cells
by Jan Martel, David M. Ojcius and John D. Young Human health requires homeostasis and coherence to respond to stress and synchronize physiological functions. This state of balance is gradually lost during aging when senescent cells accumulate and persistently secrete cytokines that promote systemic inflammation and affect various organs. The immune system is well trained to track and kill senescent cells, but immune cells become old and eventually fail to keep up. In this special issue on senescence, seven original contributions present recent advances related to the roles and characteristics of senescent cells and how senescence, aging and longevity are influenced by cancer, gut dysbiosis, immune cells, lifestyle and diet .