Skin aging

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A man with wrinkles on his face

The complex biological process of changes in the skin that goes along with age is called skin aging . This not only refers to chronological aging , but also to intrinsic aging, i.e. the genetically controlled reduced reactivity of the skin cells. It cannot be influenced. In contrast to this, the extrinsic factors (environmental factors such as UV light , chemical reagents, mechanical stress) can be influenced. That is why a distinction is made between so-called "age" and "environmental aging" (also known as "light aging") when it comes to skin aging.

Despite large individual fluctuations, studies usually consider the age of 25 as the beginning of skin aging. In general, however, it can be said that the process always begins between the ages of 20 and 30, even if the naked eye cannot perceive this at this point in time. This leads to the formation of wrinkles and lines and a loss of elasticity and resilience. This is also due to lifestyle: factors such as heat and cold , stress and an unhealthy diet, as well as alcohol and nicotine consumption can accelerate the natural aging of the skin.

Emergence

UV light creates free radicals (bond-seeking molecules) and singlet oxygen (activated oxygen). Since UVA radiation in particular penetrates deep into the skin, it generates singlet oxygen in the dermis (dermis). This causes the production of enzymes that damage the collagen fibers and thus reduce the firmness of the skin. At the same time, elastic fibers swell , which leads to a loss of elasticity in the skin . In the epidermis, UVA and UVB radiation cause skin cell damage , which can cause skin cancer .

Apart from the damage that external environmental factors can cause, the skin ages all by itself. This is genetically designed. The dermis is at the center of it all. This skin layer is made up of fibroblasts (connective tissue cells) and the connective tissue fibers collagen and elastin . The collagen ensures stability in young skin and elastin ensures the elasticity of the connective tissue . The more the skin ages, the less collagen and elastin there is in the tissue, as the cells only divide half as often as when they were young. The subcutaneous fatty tissue becomes thinner and the fat and water content of the skin decrease significantly.

The skin gets deep folds and wrinkles, its dry surface tends to crack and pseudo-scars, the epidermis becomes thinner, which makes the blood vessels stand out more clearly. The dryness of the old skin is due to a reduced activity of the sebum glands : Less fat is produced, the skin loses its elasticity and is no longer capable of regeneration, which can even lead to wound healing disorders. In addition, muscle tone also decreases with age, so that more wrinkles appear.

Molecular Aspects

Skin aging may also be triggered by certain genes that are controlled by the transcription factor NF-kappa B. The activity of this protein increases with age. After blocking this protein in mice, older mice regained a biologically younger skin condition for a short time within two weeks.

Individual evidence

  1. ↑ Keyword skin aging
  2. ^ J Krutmann, TL Diepgen, C Billmann-Krutmann. Skin aging: basics - prevention - therapy. Springer Berlin Heidelberg, 2008
  3. ↑ Keyword Ages
  4. ^ W. Stahl, U. Heinrich, S. Wiseman, O. Eichler and H. Seis: Dietary tomato paste protects against ultraviolet light-incuced erythema in humans. In: Journal of Nutrition Vol. 131, 2001, pp. 1449-1451.
  5. ↑ Skin aging: traces of time
  6. ↑ ages
  7. ^ AS Adler et al.: Reversal of aging by NFkappaB blockade . In: Cell Cycle 7, 2008, pp. 556-559 PMID 18256548

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