Neuroendocrine-immune interactions: a theoretical approach to aging.

Among the systemic theories of aging, both a 'nervous-neuroendocrine' and an 'immune' hypothesis have been proposed. The discovery of the complex interactions working among the neuroendocrine and the immune systems suggests the revision of the systemic theories of aging, particularly in the light of the recent evidence that some age-associated alterations in the neuroendocrine and in the immune systems are mutually interdependent even at very old age, as revealed by the fact that experimental manipulation of one of the two systems modifies and sometimes restores the function of the other one. These findings clearly demonstrate that at least some of the age-related alterations of the nervous, neuroendocrine and immune networks are not per se intrinsic and irreversible and that the definition of the temporal priority in the age-related deterioration is rather is rather difficult to be assigned to one or other homeostatic apparatuses.

Cancer and aging: from the kinetics of biological parameters to the kinetics of cancer incidence and mortality.

Epidemiologic and biological data strongly support the existence of a strict link between cancer and aging. In spite of the relevance of the problem, there were numerous pitfalls in epidemiologic investigation until a few years ago. An apparent decrease of cancer incidence in old age was revealed to be a misconception based on lack of sufficient appreciation for changing population size.

Dysdifferentiation hypothesis of aging and cancer: a comparison with the membrane hypothesis of aging.

Our laboratories have been testing the basic concept that the age-dependent deterioration of the molecular components of living systems may be due in part to the biochemical effects of active oxygen species. The dysdifferentiation hypothesis of aging and cancer (DHAC) as well as the membrane hypothesis of aging (MHA) are discussed and compared to each other. These two hypotheses consider cellular mechanisms through which free radical-induced alterations may lead to the aging process.