Hallmarks of aging

Aging is characterized by a progressive loss of physiological integrity, leading to impaired function and increased vulnerability to death. The hallmarks of aging are the types of biochemical changes that occur in all organisms that experience biological aging and lead to a progressive loss of physiological integrity, impaired function and, eventually, death. They were first listed in a landmark paper in 2013 to conceptualize the essence of biological aging and its underlying mechanisms. The following three premises for the interconnected hallmarks have been proposed: "their age-associated manifestation" "the acceleration of aging by experimentally accentuating them" "the opportunity to decelerate, stop, or reverse aging by therapeutic interventions on them" Over time, almost all living organisms experience a gradual and irreversible increase in senescence and an associated loss of proper function of the bodily systems. As aging is the primary risk factor for major human diseases, including cancer, diabetes, cardiovascular disorders, and neurodegenerative diseases, it is important to describe and classify the types of changes that it entails. After a decade, the authors of the heavily cited original paper updated the set of proposed hallmarks in January 2023. In the new paywalled review, three new hallmarks have been added (not included or categorized below): disabled macroautophagy, chronic inflammation and dysbiosis, totaling 12 proposed hallmarks. The nine hallmarks of aging of the original paper are grouped into three categories as below: Primary hallmarks (causes of damage) Genome instability Telomere shortening (or telomere attrition) Epigenetic alterations Loss of proteostasis Antagonistic hallmarks (responses to damage) Deregulated nutrient sensing Mitochondrial dysfunction Cellular senescence Integrative hallmarks (culprits of the phenotype) Stem cell exhaustion Altered intercellular communication Primary hallmarks are the primary causes of cellular damage.