<Ul> <Li> genomic instability (mutations accumulated in nuclear DNA, in mtDNA, and in the nuclear lamina) </Li> <Li> telomere attrition (the authors note that artificial telomerase confers non-cancerous immortality to otherwise mortal cells) </Li> <Li> epigenetic alterations (including DNA methylation patterns, post-translational modification of histones, and chromatin remodelling) </Li> <Li> loss of proteostasis (protein folding and proteolysis) </Li> <Li> deregulated nutrient sensing (relating to the Growth hormone / Insulin - like growth factor 1 signalling pathway, which is the most conserved ageing - controlling pathway in evolution and among its targets are the FOXO3 / Sirtuin transcription factors and the mTOR complexes, probably responsive to caloric restriction) </Li> <Li> mitochondrial dysfunction (the authors point out however that a causal link between ageing and increased mitochondrial production of reactive oxygen species is no longer supported by recent research) </Li> <Li> cellular senescence (accumulation of no longer dividing cells in certain tissues, a process induced especially by p16INK4a / Rb and p19ARF / p53 to stop cancerous cells from proliferating) </Li> <Li> stem cell exhaustion (in the authors' view caused by damage factors such as those listed above) </Li> <Li> altered intercellular communication (encompassing especially inflammation but possibly also other intercellular interactions) </Li> </Ul> <Li> genomic instability (mutations accumulated in nuclear DNA, in mtDNA, and in the nuclear lamina) </Li> <Li> telomere attrition (the authors note that artificial telomerase confers non-cancerous immortality to otherwise mortal cells) </Li> <Li> epigenetic alterations (including DNA methylation patterns, post-translational modification of histones, and chromatin remodelling) </Li>

Which of the following words means characteristic of old age