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September 01, 2016 23:11

Aging and photoaging

said that the fashion for a tan imparted Parisian legendary Coco Chanel, when he returned from a cruise on the Mediterranean, was struck by the pale Parisian beauties bronze tan.Soon capricious fashion made a turn of 180 °, and the ladies had not leave the house without hats with a wide brim, long gloves and veils, go to the beach, where at first timidly, then more boldly bared their bodies, substituting the hot rays of the sun.

According to another theory, the fashion for a tan appeared when pale skin became associated with hard work indoors factories and tan became a privilege of those who could afford to spend a lot of time outdoors, relaxing and doing sports.Whatever it was, in almost all European countries and in America, the tan has become a symbol of health and an active lifestyle, and so many people, especially at a young age, lay under the scorching sun to burn and dizziness, trying to get him.

In America, a generation that was so active to be friends with the sun, was a generation of peop

le born during the post-war baby boom in the 40-50-e godi or the generation of baby boomers (baby-boomers).Years passed, and doctors began to notice that the aging of the skin at the baby boomers has its own characteristics - sharp wrinkles, roughness, skin roughness, pigmentation spots, the presence of areas of compacted and flaky skin twigs dilated vessels in the cheeks.Such changes are detected only in the areas exposed to the strong solar radiation, while in areas usually protected from the sun (for example, on the lower abdomen, and inner thighs, etc.), leather, usually looks better.It took a thorough research before doctors came to the unanimous conclusion - not age, and solar radiation is responsible for the appearance of these symptoms.As it turned out, the UV radiation, although it has such a devastating effect as ionizing radiation, nevertheless has sufficient energy to cause damage to skin DNA and other molecules.

Who are the following signs of skin sun damage, or fotostatosreniya:

  • wrinkles appear in areas of damaged collagen;
  • skin unevenness occurring in areas of atypical accumulation of elastin (soyalnechny elastosis);
  • dry skin;
  • dilation of superficial blood vessels (telangiectasia);
  • age spots (solar lentigines);
  • actinic or solar, keratosis (patches compacted reddish, scaly skin).

photoaging Most often seen in fair-skinned people after the age of 50 years as people with it appears less dark skin.photoaging concept has revolutionized the cosmetic.Prior to this, scientists believed that aging can not be prevented, or rejuvenate the skin grown old, and that all attempts to create a means of smoothing wrinkles and restore skin youthful glow, are doomed to failure.It turned out that the skin damaged by the sun, maintains the stamina that you can awaken.Now developed a number of tools and techniques that allow you to partially eliminate the signs of photoaging.Although they are advertised as a means of "wrinkles" or "aging", it should be understood that in this case we are not talking about the true rejuvenation, and on the "treatment of" (or more precisely - recovery) of the skin damaged by the sun.

currently accumulated extensive information about the negative effects of UV on the skin.The spectrum of ultraviolet rays represented by three study groups.

  • Ultraviolet light C (UVC, short UV, far UV) - beams with the shortest wavelengths (100-280 nm).They have the most damaging effect on the human body.However, their effect is minimal, since they are absorbed by the ozone layer and do not reach the almost ground
  • The ultraviolet rays (UVB, mid UV) - with an average rays wavelength range (280-320 nm).They damage the skin as much as possible, but their effect is significantly attenuated by clouds, and penetration of clothing and detain ordinary window glass.Adsorption UVB and dispersion in the atmosphere occurs when the sun is low on the horizon (early morning and late evening), at high latitudes, as well as in winter.

lowest absorption and dispersion of these rays is celebrated on the floor the day, at low latitudes, and in the summer.

  • ultraviolet rays A (UVA, long UV, near UV, black light) - beams with the highest indicators of wavelengths (320-400 nm) The damaging effect of UVA is 1000 times weaker than UVB.However, they are much better reach the earth's surface, and penetration is independent of the time of day, season and latitude.It is known that these rays are not filtered by the ozone layer, penetrate through clouds clothes are not tinted windowpanes.That is why in many modern buildings use tinted glass, which is not only defined the architecture and aesthetic solution, but also the factor of protection from UVA.

source of ultraviolet radiation is not only the sun, but tanning beds and lamps.It is believed that a small proportion of UV light can produce a gas-discharge lamps.With regard to fluorescent lamps and halogen lamps, television screens and computer screens, they are not sources of ultraviolet radiation.It is important to remember that the white sand, snow, water reflects up to 85% of solar radiation.Therefore, while on the beach or in the mountains, a person gets almost twice as much energy due to reflection and scattering of light.

ultraviolet rays A and B differ in the depth of penetration into the skin - it is directly proportional to the wavelength.It is known that 90% of the stratum corneum blocked UVB, while UVA can penetrate into the deeper layers of the epidermis and more than 50% of them may fall into papillary and reticular dermis.That is why when exposed beams in the epidermis changes occur, and when exposed to the rays A - structural changes in the basic substance of the dermis and its fibrous structures, microvasculature and cell elements.

Mechanisms of action of ultraviolet rays on the skin and their effects are well understood.It is known that UVC have expressed mutagenic influence.UVB causes sunburn, partly sunny tan.The main negative consequence is proven UVB carcinogenesis, which is induced as a result of cell mutations.Ultraviolet rays A cause skin pigmentation, ie. F. Tan.These rays are the least eritemogennymi, which is why the spectrum of ultraviolet radiation is represented in tanning lamps.UVA as well as UVB, cause carcinogenesis, it is known potentiating effect ray beams A against B. Some researchers believe that the beams A play an important role in the development of melanoma than the beams B. In this connection it must be stressed the importance of applying sunscreensmeans of action of the rays A and B simultaneously.

The combined effect of the action on the skin to ultraviolet rays includes a number of morphological changes.It is known to influence proliferation and differentiation of keratinocytes, fibroblasts, melanocytes (stimulation alteration of cellular elements, impaired DNA repair).It is proved that the combined effect of the rays A and B leads to a number of serious violations of the local immune surveillance.In particular, account generation number immunosupressivngh cytokines in the skin (for example, IL-10), reducing the number of NK lymphocytes involved in the elimination of tumor cells, the appearance of CD8-lymphocyte stimulating apoptosis Langerhans cells, induction of epidermal trans tsisizomerizatsii urocanic acid (endogenouscomponent credited immunosuppressive effect).In addition, UVA is the main reason for the development of photosensitivity.Most of dermatoses associated with increased congenital or acquired sensitivity to UV light, occur or are aggravated by the impact of the long-wavelength range is.These dermatoses include photoallergic reactions, porphyria, solar urticaria, lupus erythematosus, xeroderma pigmentosum and other diseases.

It should be emphasized that the ultraviolet rays are associated with ryznovidn A spine-aging - photoaging.It is characterized by certain morphological manifestations other than biological aging.Under the influence of UVA in the epidermis there is an uneven thickening of the horny layer of the epidermis and in general due to the uneven acceleration of basal keratinocyte proliferation and abnormal keratinisation processes.developing dysplasia keratinocytes.The dermis is formed by chronic inflammation, fibrous structures are destroyed, especially elastic fibers (homogenization, thickening, tightening and fragmentation of elastic fibers, reducing their diameter and number - "solar elastosis"), there are serious changes in vessels of small caliber.Last in the future lead to the restructuring of the microvasculature and the formation of telangiectasias

known that prolonged exposure of UVA, such as excessive use of tanning beds causes structural changes in the skin, similar to the long exposure to the sun.It is appropriate to emphasize the importance of metered use tanning beds.

There are acute and chronic UV exposure, causing a variety of clinical manifestations.

Clinical signs of acute UV exposure include sunburn and skin pigmentation.Sunburn is a simple dermatitis is manifested by erythema and edema (grade 1) or erythema and the formation of blisters (2nd degree).Burn 3rd degree is extremely rare, mostly in infants, and is accompanied by a heat shock.It is believed that the occurrence of sunburn 1st degree possible, if a person within 24 hours was minimal erythema dose of 4 and 2 nd degree - 8. pigmentation or sun tan, there is instant and delayed.Instant darkening of the skin occurs within a few minutes of sun exposure and is associated with photooxidized already synthesized melanin and its rapid redistribution of dendritic melanocytes and, later, in the epidermal cells.Delayed pigmentation occurs 48-72 hours and is associated with the active synthesis of melanin in the melanosomes, the increase in the number of melanocytes and activation of synthetic processes in the previously inactive melanocytes.These changes are a reflection of the protective properties of the skin in response to ultraviolet light.Delayed pigmentation can also be explained by the formation of secondary and post-inflammatory pigmentation as a result of a simple dermatitis or burns.

Clinical signs of chronic exposure to ultraviolet radiation are: vascular changes, pigmentation disorders, skin novobrazovaniya, changing turgor, elasticity, skin pattern.Vascular changes due to chronic exposure UFO presented persistent diffuse erythema, telangiectasia formation, ecchymosis in areas most exposed to radiation (face, hands, parietal and occipital area, back of the neck, and others.).Pigmentation disorders appear as freckles, solar lentigines, dyschromia, idiopathic guttate hronicheskiskogo gipomelanoza and poykilodermii.This complex clinical manifestations, along with signs of photoaging, called in English literature "skin damaged by the sun" ( «sun-damaged skin»).Excessive UVR most often associated with the development of skin tumors such as actinic keratosis, basal cell carcinoma, flat cell carcinoma, melanoma.

Changes turgor, skin elasticity and drawing are the basis for photoaging.Clinically, photoaging skin appears dry, its rough, stressed skin pattern, decreased skin turgor and elasticity.The consequence of these changes are minor and superficial wrinkles.In addition, when photoaging noted yellowish tinge to the skin, dyschromia, lentigines, telangiectasias, seborrheic keratoses, comedo senilis.It is noteworthy that the complex changes in the skin associated with chronic exposure UFO is described well in dermatology at the beginning of the last century (eg, "skin of seafarers", "skin peasants", "diamond-shaped atrophy neck», Favre-Racouchot disease, etc.)..

In assessing the nature of age-related changes of the skin is important to consider a variety of aging.Morphological and clinical signs of photoaging have their own characteristic pattern that differs from that in other types of aging.