Skin Tone Loss

Causes of Loss of Tone

Conceptually, aging can be defined as a progressive, time-dependent deterioration of the body's ability to respond to environmental changes. Two types of skin aging have been codified: intrinsic and extrinsic.

Intrinsic aging

Intrinsic aging depends on advancing age and is influenced by genetic background ( chronoaging ). Causes hypotrophic alterations of the skin with alteration of all the components and functions of the integumentary system.

In particular, the structure of the fibrous proteins that make up the dermis (collagen and elastin) is modified.

The cells involved in their production, the fibroblasts, with the passing of the years, not only slow down their own rhythms and their efficiency, but develop smaller sized collagen and elastin cells. As a result, the dermis thins and the supporting scaffolding on which the skin rests loosens its texture, becomes more flexible and begins to give way. At the level of the epidermis, the mitotic activity of the basal cells is reduced and the barrier function becomes less effective. In the more superficial layers of the corneum, on the other hand, there is an accumulation of dead cells, which causes thickening and chromatic irregularity of the epidermis. The cells deposited on the stratum corneum, in fact, not only have a slower turnover, but retain melanin, giving rise to more or less evident spots. The facial features are modified by the accumulation of subcutaneous fat in unusual sites and by the loss of elasticity of the dermis.

When the cellular metabolism slows down, the skin faces a profound revolution, which occurs on the face with the appearance of relaxation, loss of elasticity and deep wrinkles. The first wrinkles are those of expression, caused by facial contractions which, becoming repeated, are imprinted on the underlying dermis which is simultaneously losing its tone. With the loss and alteration of collagen and elastic fibers, the tissues begin to relax, the skin loses its support and the oval of the face begins to deform.

Role of free and UV radicals

The environmental factors that lead to the formation of free radicals, therefore the main causes of skin aging, consist mainly of solar radiation, smog, and smoke.

There is a close relationship between skin aging and free radical oxidative damage, since polyunsaturated fatty acids, which are the main constituent of the stratum corneum, are particularly susceptible to attack by these molecules (lipid peroxidation). Furthermore, free radicals cause the depolymerization of polysaccharides, such as hyaluronic acid, which causes premature cellular aging in the skin.

The UVA rays penetrate the dermis damaging the collagen and elastic fibers: the new fibers that are formed can show alterations that give life to an opaque fabric, wrinkled and not very compact.

One of the most credible hypotheses holds that actinic radiations, inducing the formation of free radicals in the skin, are normally contrasted by its natural antioxidant defenses; however, when the dose of these radiations is high, or the natural defenses are insufficient, it is no longer possible to maintain the levels of free radical concentrations below the critical concentrations.

1 Puizina-Ivić N, Mirić L, Carija A, Karlica D, Marasović D. Modern approach to topical treatment of aging skin. Cell. Antropol. 2010 Sep.34 (3) 1145-53.