Is it possible to overcome aging?
Today and tomorrow cell therapy
Leonid Yu. Prokhorov
© Leonid Yu. Prokhorov, 2022
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It is believed that one of the main causes of skin aging is a decrease in the ability of skin fibroblasts to divide with age. As a result of this process, the number of fibroblasts in the skin decreases, and they become less active. Therefore, if to stimulate proliferative and synthetic activity of fibroblasts, in any way, then it will be possible to improve skin conditions (Krikheli et al., 2004).
In addition, in the skin there occurs a decrease of the amount of collagen fibers and their hydration, they lose the ability to swell and become rigid; as a result the turgor is decreased, and wrinkles appear. At the same time, the skin loses lipids, its protective mantle breaks down, and it becomes vulnerable to disruption (Guide of gerontology, 2005).
As the number and activity of fibroblasts is reduced, the remaining cells are unable to compensate for senile changes in the skin. Therefore, if to increase the number of young active fibroblast cells in the skin, it is reasonable to wait for the improvement of its condition due to the fact that fibroblasts will produce young collagen and elastin, and this will increase the elasticity of the skin and its turgor; as a result, the wrinkles well be smoothed.
METHODS OF SKIN REJUVENATION
In order to correct age-related changes in the skin, there is a variety of currently used methods (peels, polishing, lifting, etc.) and preparations (toxin of botulism, components of extracellular matrix and connective tissue, etc.). Many of these methods are aimed at stimulating skin cells, in particular fibroblasts. However, it can be possible to solve the problem in
another way by increasing the number of fibroblasts in the skin by means of transplanting them to the places where needed.
Before transplantation of fibroblasts became a reality, researchers had to solve many methodological questions, including those of safety of similar procedures.
Significant progress has been achieved in this regard when researchers became able to cultivate the cells, i. e. maintain the viability of fibroblasts outside the body, or in other words in vitro. In 1961, L. Hayflick and P. S. Moorhead (Hayflick, Moorhead, 1961) reported that even under optimal conditions of in vitro cultivation, human embryo fibroblasts were only capable of dividing a limited number of times (50 ± 10). In subsequent studies, this observation was repeated many times. The last phase in the life of cells in culture hase been identified as cellular senescence, and the phenomenon received the name of the author as Hayflick limit.
After the establishment of Hayflick limit and as a result of numerous studies, it was found that normal fibroblasts in culture retain a diploid karyotype and have a limited life expectancy. In addition, normal cells lack oncogenic potency. These requirements to cultures of normal cells were issued in the form of normative documents.