When you are 20, you drink all night , walk,
and in the morning not a trace remains on you.
When you are 40, you drink all night , walk,
and in the morning all consequences are obvious.
When you are 60, you sleep all night
and in the morning you look
as if you walked and drank for the whole night.
(Unknown Author)
Along with hypertension and atherosclerosis, autoimmune diseases are characteristic of the aging body. According to one theory, the above “gerontal triad” is caused by the age-related and accidental involution of thymus resulting in weakening of positive and negative selection of T-lymphocytes followed by activation of auto-aggressive clones of immunocompetent cells. In connection with this, information about rejuvenation effect (with external signs) and reproductive function improvements after experimental or clinical application of stem cells should be regarded as important.
One of the key issues of gerontology is identity of cell and multi-cell body aging.
We found the starting point for the development of the new way of apprehending aging – from the point of view of the Body Stem Spaces Depletion Theory.
Stem space is a pool of regional (“adult”) stem cells (mesenchymal, neural, hematopoietic, basal stem cells of skin, bowel, endocrine epithelium; ciliary sulcus pigmented cells etc.) intended for restoration of cell losses in a certain tissue in the process of body remodeling.
Body remodeling is a continuous renewal of cells in all body organs and tissues by the cells from stem spaces during the whole lifetime of the multicellular body of a mammal whose differentiated cells have a limited life span.
It is known that cell apoptosis and renewal pace varies in different organs and tissues. In this case, physiological reaction is realized in two ways: 1) duplication of differentiated cells with formation of progeny with identical geno- and phenotype; 2) substitution of the dying differentiated cells with the progeny of non-differentiated early precursor cells. In the second case, neocytogenesis involves multipotent stem cells capable of self-renewal and formation of the committed сolony-forming cells final differentiation of which is influenced by the surrounding microenvironment (growth factors and cytokines).
Thus, for understating of aging mechanisms, we offer the Body Stem Spaces Depletion Theory the main principles of which are as follows:
- Aging is a continuous shrinking of body stem spaces.
- The number of stem cells in these spaces is genetically predetermined, which defines size limits, or proliferative potential of each space.
- Stem space size determines ageing rate of each body, organ, tissue and system.
- After depletion of stem space cell reserve, ageing intensity and rate is determined by ageing mechanism of somatic differentiated cells within Hayflick limit.
- In post-natal ontogenesis, stem spaces widening necessary for longer life expectancy and better life quality is possible via administration of allogenic fetal progenitor cells on condition of simultaneous re-programming of the recipient’s immune system.
According to the main principle of this theory, aging is a continuous shrinking of body stem spaces or pool or regional (“adult”) stem cells from which cell losses in a certain tissue are compensated in the process of body remodeling, which is continuous and life-long. The number of stem cells in these spaces is genetically predetermined, which defines size limits, or proliferative potential of each space. Stem space size determines ageing rate of each body organ, tissue and system. After depletion of stem space cell reserve, multicellular body ageing intensity and rate is determined by ageing mechanism of somatic differentiated cells within Hayflick limit. In other words, in post-natal ontogenesis widening necessary for longer life expectancy and better life quality is possible via administration of high doses of allogenic fetal progenitor cells on condition of simultaneous re-programming of the recipient’s immune system.
