Why does the skin age?
Do you notice on your reflection in the mirror the first signs of skin aging, such as wrinkles and dark spots? The period during which a person has smooth and elastic skin is very limited, and time and sunlight are to blame for this.
Skin aging is caused by a combination of natural aging and exposure to sunlight. A little sunlight is simply necessary for a person to maintain vitamin D levels and prevent the development of seasonal depression. However, too much radiation causes irreversible damage to the skin.
An inescapable time factor is added to this, which as a result leads to sagging of the skin, the appearance of wrinkles and pigmentation disorders, which are characteristic signs of aging.
Human skin has two layers: the epidermis and the dermis. The epidermis is an external barrier of the skin that protects us from the effects of harmful environmental factors, such as bacteria and ultraviolet radiation. And the dermis under it, containing a large amount of collagen and other proteins, is responsible for both the strength and elasticity of the skin.
Throughout life, both layers of the skin suffer quite a lot and eventually accumulate irreversible damage. Why can't the skin repair these damages?
Skin cells lose contact
The dermis contains an exceptionally complex structure of extracellular matrix proteins, including collagens and other proteins that provide skin elasticity, such as elastin.
Dermal fibroblasts producing these proteins are tightly fixed between protein structures and attached to them. With age, the extracellular matrix progressively loses its integrity due to fragmentation of protein structures.
Fibroblasts lose contact with the extracellular matrix due to the slow enzymatic destruction of the protein framework of the dermis. This leads to changes in the structure of cells and severe violations of their functions. The production of proteins by fibroblasts decreases, which contributes to the further destruction of the extracellular matrix.
This vicious circle leads to a significant decrease in skin elasticity and deterioration of its appearance. Why this is part of the normal aging process is unclear, but researchers believe that the reason for triggering the destructive cascade is a combination of oxidative DNA damage, physiological cell aging and chronic inflammation.
However, the dermis is not the only culprit of what is happening.
The cells of the epidermis and the destructive effect of ultraviolet
Despite the fact that we are all to a certain extent subject to a natural deterioration of the elasticity and integrity of the extracellular matrix, exposure to sunlight significantly aggravates the situation.
However, when conducting laboratory experiments, fibroblasts themselves do not react to the direct effects of ultraviolet light. Researchers believe that instead of them, epidermal cells react, releasing chemical compounds in response to the action of irradiation, penetrating into the dermis and stimulating the release of enzymes into the extracellular matrix.
It is believed that this complex interaction leads to the appearance of deep wrinkles, which are a characteristic sign of UV-induced skin aging.
Adipose tissue and aging
As the body ages, a natural thinning of subcutaneous fat occurs, leading to sagging skin. However, until recently, researchers have not been able to identify the relationship between UV-induced damage and adipose tissue. Ultraviolet rays do not penetrate to the depth of subcutaneous fat.
However, not so long ago, scientists discovered previously unknown deposits of fat in the deep layers of the dermis, which can penetrate into the exposed upper layers of the dermis.
These specialized fat cells can also respond to compounds released by epidermal cells. With the chronic damaging effect of ultraviolet radiation, these fat cells die and are replaced by scar tissue.
Can this information help us avoid the inevitable accumulation of skin damage? Limiting the exposure of sunlight to the skin will definitely reduce the amount of damage caused.
To date, no one knows how to stop the natural aging process. However, researchers continue their work and do not lose hope of finding the "holy Grail" of aging.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru
according to Medical News Today: Why does our skin age?
05.09.2017