Free radical theory of aging: view against the reliability theory

The reliability theory approach to the free radical theory of aging is presented. First, the structural and functional inhomogeneity - hierarchy - of living systems has been taken into account. Hence, the existence of the finite number of critical structures - supervisors - in the system has been postulated. Second, I have postulated the stochastic nature of age-changes in the supervisors, paying particular attention to oxygen free radicals as the by-products of normal oxidative metabolism. Third, according to the cooperativity of main processes in biological systems, the existence of the threshold values of the reliability parameters of the supervisors has been postulated. In the terms of this reliability free radical theory of aging it becomes possible to explain the character of age-changes in mortality data for humans and animals; to explain how the linear kinetics of accumulation of free radical damages in the cellular targets (supervisors) can lead to the exponential kinetics of the mortality rate growth with age, i.e., to deduce the so-called Gompertz law of mortality; to explain the nature of the well-known empiric interspecies correlations between the maximum life span values and metabolic factors; to estimate species-specific life span potentials of humans and animals. The chromosomes of neural postmytotic cells have been suggested to function as the supervisors. In the terms of the theory it has been estimated that the life span of primates could run up 250 years but for the damages due to the oxygen free radicals.