Cellular background of non-senescence

A. Khalyavkin
Institute of Biochemical Physics of RAS, Moscow, Russia

The gradually loss of the proliferative capacity in fibroblasts and other cells in vitro may be a manifestation of cellular maturation and terminal differentiation but not of the true senescence of cells. The limitless proliferative potential which somatic stem-like cells are thought to possess is clearly revealed by means of in vitro restoration of the stem cell supporting microenvironment, or by removing differentiating stimuli from the cell culture, or by adding differentiating inhibitors to cultural medium, etc. The same effect can be achieved by the constitutive expression of proto-oncogenes, which encode the nuclear immortalization proteins of the MYC type and some others. The important function of these proteins is the blocking of cellular differentiation. The decade later there are the similar results, obtained by means of telomerase constitutive expression and the same plausible explanation of it via differentiation blocking. Moreover, heterochronic parabiosis reveals the cell aging reversibility in vivo (Conboy et al., 2005). The foregoing proves that anti-aging processes can, in principle, successfully counteract cellular deterioration and shows the essential futility of attempting to search the aging primary causes by purely cytological methods at the cellular level. On the other hand, the Strehler-Mildvan correlation between the parameters of mortality statistics for people living in different countries/conditions is exactly the same as the mortality pattern for hypothetical populations of potentially non-senescent organisms, which do, however, experience senescence as a result of functioning in living conditions that to varying degrees prevent the total self-maintenance of the organisms.

Keywords: Cellular non-senescence, Rate of aging, Environmental influence