Fig. 5

Quiescence and senescence in cardiomyocytes. Cardiomyocytes are proliferative during the fetal state but exit the cell cycle shortly after birth to enter a quiescent state. Stimuli including excessive glucose, insulin, or reactive oxygen species can induce a pathological senescent state. Cell cycle arrest with p53 upregulation leads to quiescence with inhibition of mTOR signaling but senescence with activation of mTOR signaling. In vitro culture conditions using high glucose or high insulin may also induce a senescent state and inhibition of these processes and promotion of quiescence may be important to promote cardiomyocyte maturation