Cellular aging (The hayflick limit) and species longevity: A unification model based on clonal succession

摘要: A model is presented which proposes a specific cause-and-effect relationship between limited cell division potential and the maximum lifespan of humans other mammals. It based on clonal succession hypothesis Kay states that continually replicating beds (e.g. bone marrow, intestinal crypts, epidermis) could be composed cells with short, well-defined potentials. In this model, these are proposed to exist in an ordered hierarchy establishes sequence for divisions throughout organism's lifespan. The depletion at all hierarchical levels leads loss bed function sets intrinsic limit species longevity. proliferation defined allows calculation time and, ultimately, organism mortality. existence small number (n) critical within defines death as inability any one produce cells. consistent major observations related cellular organismic aging. particular, it links PDLs (population doubling limit) observed various their mean lifespan; explains slow decline PDL age donor; thermodynamically stable disease-free population; can explain why tissue transplants outlive donors or hosts.