Photoaging treatment. What is skin photoaging? Who is most susceptible to photoaging?

As the name suggests, photoaging is the process of changing the condition and structure of the skin caused by regular exposure to sunlight. It is also called heliodermatitis, actinic dermatitis, or premature skin aging. Photoaging should not be confused with natural age-related aging of the skin caused by hormonal changes in the body. Of course, these two processes can go in parallel, but they still have different symptoms, signs and causes, which means they need to be treated differently.

Causes and consequences of photoaging

The first ideas about photoaging came in the late 1980s, when it was discovered that the sun may be the cause of what was previously thought to be exclusively age-related skin changes.

Today, dermatologists and cosmetologists around the world note differences in the processes of chrono- and photoaging of the skin, highlighting various causes, symptoms and consequences of the changes. Age-related aging of the skin depends less on external factors and more on genetic predisposition and hormonal processes occurring in the body. Photoaging, on the contrary, is considered a special type of damage to the skin and is not caused by internal processes of the body.

The main reason for such changes is excessive exposure to sunlight on the skin and, as a result, disruption of the epidermal renewal process. Wear and tear of cellular structures as a result of exposure to harmful factors, in this case UV radiation, manifests itself in loss of tone, dryness, dullness and sagging skin, the appearance of wrinkles and age spots.

It is worth explaining that it is the excessive exposure to UV radiation on our skin and neglect of protective equipment that causes harm. This becomes especially clear when comparing exposed and inaccessible areas of the skin. In small doses, the sun is necessary for our body to strengthen the immune system, synthesize vitamin D and serotonin.

How does photoaging occur?

Today, photoaging is usually classified according to the Glogau scale, which distinguishes four stages of skin aging depending on age and the signs that appear. According to this classification, our skin gradually goes through all stages of changes and, depending on the condition, appropriate treatment must be prescribed.

1. No wrinkles. Premature photoaging is manifested by light pigmentation, the absence of visible deep wrinkles and the absence of keratosis. Age from 20 to 35 years.
2. Moderate photoaging, manifested by the formation of facial wrinkles around the mouth and eyes. There are pronounced changes in skin pigmentation. It is observed between the ages of 35 and 50 years.
3. Severe photoaging is characterized by an abundance of wrinkles, visible even at rest, the presence of obvious symptoms of telangiectasia, as well as dyschromia. Traditionally it appears over the age of 50 years.
4. Photoaging of extreme severity is observed between the ages of 60 and 80 years. The skin becomes yellow-gray in color, pronounced wrinkles appear on the entire surface of the skin, and pre-malignant changes in the skin may be present.

Who is most susceptible to photoaging?

It is believed that the main protector of human skin from ultraviolet radiation is melanin. The more pigment the skin cells produce, the less damage the sun's rays cause. From this we can conclude that the lighter the skin, the higher the risk of early manifestations of photoaging.

Women are also highly susceptible to ultraviolet radiation during periods of hormonal changes (pregnancy, menopause, various hormonal disorders). This happens because an imbalance of estrogen and progesterone increases the skin's sensitivity to UV radiation. As a result, increased skin pigmentation.

How to protect your skin from photoaging

Maintaining youthful and attractive skin is not an easy task. However, it is still possible to slow down photoaging. It is enough to remember to use sunscreen and not neglect it not only at the resort, but also in the city. Don't forget that UV radiation comes to us not only from direct sunlight on a hot summer afternoon. Ultraviolet radiation reaches the earth around the clock, it can be reflected from various surfaces, pass through clouds, clouds, water and even light clothing, which is why it is so important to use protective products all year round and regardless of weather conditions.

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Sun care with maximum protection Kiehl's SPF 50

Uriage Bariesun Sunscreen for Sensitive Skin

Sunscreen body cream SPF 30, Clinique Sun

Soothing tanning cream-activator for face and body After Sun Tan Maximizer from Lancaster

Sunscreen dry spray Garnier Ambre Solaire

Many years ago, the magnificent Coco Chanel brought tanned skin into fashion. Today, the love for chocolate tanning has resulted in the problem of premature skin aging or photoaging. The reason for this aging is the negative impact of ultraviolet rays, and today the efforts of the world's leading cosmetologists and dermatologists are aimed at finding effective methods to neutralize this effect.

Scientists have already established that photoaging is very different from age-related aging. It has its own biochemical, histological and clinical manifestations. Photoaging is also called actinic dermatitis or heliodermatitis, which once again emphasizes its special nature, different from ordinary aging. Today, when tanned skin is considered a sign of health and beauty, it is very important to learn how to properly prevent photoaging of the skin and combat its consequences.

Mechanism of photoaging

We all know that life on our planet is impossible without sunlight, but everything should be in moderation. Excessive exposure to the sun leads to burns and premature aging of the skin. Excessive sunbathing causes damage to the top layer of skin and changes in it that look like aging.

Under the influence of ultraviolet rays, the mother cells of the epidermis - keratinocytes - begin to rapidly divide. These same cells are responsible for the renewal, thickening and keratinization of the epidermis. Increased division of keratinocytes leads to uneven thickening and keratinization of the epidermis.

And this is followed by changes in the deeper layers of the skin. In the dermis, the destruction of elastin fibers begins, they become denser, curled, and their number decreases. Gradually, pockets of inflammation appear in the skin. And stagnation in the capillaries gradually leads to changes in the blood flow. Outwardly, it looks as if the skin began to age quickly and prematurely, and the first wrinkles appear.

Signs of photoaging

To distinguish young, healthy skin from aging and fading skin, you don’t need to be a specialist at all; all you need to do is just look at a person. But in cosmetology they distinguish six main signs that help determine healthy skin:

• uniform color without ;
• elasticity;
• normal texture, no wrinkles or scars;
• normal moisture;
• absence of visible signs of disease;
• good resistance to adverse factors.

When photoaging the skin, it develops the imperfections characteristic of normal aging, such as the appearance of wrinkles and uneven color, dryness and thinning.

Recently, the popularity of such a method of skin rejuvenation as photorejuvenation has increased. which is based on the complex effects of thermal and light energy. After this procedure, there is also an improvement in skin texture, lightening and evenness of color. In addition, this procedure has a minimum of side effects.

Tanning without the sun (Video: “Tanning from a tube”)

What should those girls do who want to show off their chocolate skin tone, but at the same time not expose it to the risk of premature aging? One of the best ways is the so-called “self-tanning”. Products that color the skin a natural golden color have been known for a long time; they have been used to even out skin tone and camouflage areas without pigmentation, which can occur, for example, with vitiligo.

Typically, such preparations contain ketosaccharides, which are derivatives of fructose and glucose. Such substances temporarily color the upper layer of the epidermis tan. At the same time, they are completely harmless to the body, since they do not affect the formation of melanin in the skin, are not absorbed into the blood and do not in any way change skin cells. In this case, the color on the skin can remain for 5-6 days.

To get a beautiful, even color using self-tanning, the surface of the skin must have an acidic reaction, so you cannot use soap before applying it. You can also do a light peeling, since uneven thickness of the stratum corneum of the skin can cause uneven color distribution. And immediately before applying self-tanning, it is advisable to consume more foods rich in carotene, for example, carrots or oranges.

They paint the skin a light golden color and improve the quality of the resulting tan.

Ultraviolet rays can cause skin aging, which differs from natural aging. Processes of negative changes can occur very quickly and manifest themselves when the sun is abused, without being tied to a person’s age limit.

This phenomenon is called photoaging. Ultraviolet rays, the culprits of premature aging, can be of any nature: emitted by the sun or artificially created in a solarium.

The problem is sometimes called actinic dermatosis or heliodermatitis. Skin aging associated with exposure to ultraviolet radiation can occur simultaneously with age-related aging. These processes will, in this case, proceed in parallel relative to each other.

The effect of ultraviolet radiation on the skin occurs through changes in the behavior of mother cells (keratinocytes). Their increased division contributes to keratinization of the epidermis and its uneven thickening.

Further development of the negative process moves to deeper layers and damages elastin fibers. Their volume decreases and they become denser. If the level of ultraviolet radiation on the skin does not decrease, then problems with blood flow begin.

An important feature of the problem is that photoaging occurs not only from direct ultraviolet rays, but also from radiation reflected from the surfaces of objects, as well as water, soil, sand (on the beach).

What is skin photoaging, a specialist will tell you in the video below:

Classification

Photoaging can occur in different forms:

• chronic process is skin aging, which manifests itself through the following manifestations:
  • change in turgor,
  • the appearance of neoplasms,
  • impaired skin elasticity,
  • changing the pattern;
• acute course The disease is manifested by sunburn and skin reaction in the form of pigmentation.

Localization

Areas of the skin that are usually open to such influence are exposed to the destructive effects of ultraviolet radiation:

• on the neck,
• skin on the face,
• Hands,
• neckline,
• forearms.

Causes

Excessive exposure to ultraviolet rays initiates the following phenomena in the skin:

• changes occur at the cellular level, leading to damage to the skin;
• Skin aging is promoted by mutations in mitochondrial DNA.

Symptoms of skin photoaging

Skin aging caused by ultraviolet radiation is manifested by the following signs:

• increased wrinkling of the skin,
• in certain areas (),
• Slow wound healing is observed with skin injuries,
• the skin loses its elasticity,
• the appearance of wrinkles and folds,
• violation of skin color (),
• loss of skin tissue tone, the skin becomes flabby.

Photoaging is not observed in children. But prolonged exposure to the sun can later affect rapid aging in adulthood.

Diagnostics

Photoaging is determined by external signs of skin changes. If the process of rapid aging of the skin has begun and at the same time its turgor has changed, peeling is noticeable and, possibly, pigmentation has appeared, folds and wrinkles have appeared, then we can talk about photoaging.

Treatment

To stop the photoaging process, you must complete the following tasks:

• eliminate peeling,
• normalize skin balance (water-lipid),
• moisturize the skin at a deep level,
• restore uniform color and texture of the skin,
• take measures to protect skin cells from the action of free radicals.

Skin photoaging (photo)

Photoaging and how to properly restore skin after summer - the topic of the video below:

In a therapeutic way

Methods used:

• laser resurfacing,
• microdermabrasion,
• dermabrasion,
• mesotherapy,
• photorejuvenation,
• biorevitalization.

Peels have a complex effect on the skin:

• moisturize,
• bleach,
• exfoliate.

Medication

Phytoprotectors are used in the treatment of photoaging. These substances have a restorative effect on skin that has undergone premature aging.

Phytoprotectors are of two types:

• Those that act on the skin through oral administration of drugs:
  • aspirin,
  • lycopene,
  • antihistamines,
  • superoxide dismutase,
  • beta carotene,
  • vitamins E,
  • selenium,
  • vitamin C,
  • flavonoids,
• Preparations that are used externally; Products that contain substances that protect the skin from photoaging:
  • screens – help reflect ultraviolet rays from the surface of the skin;
  • filters - cream components absorb ultraviolet rays, thereby neutralizing their harmful effects.

Protective means are presented:

• creams:
  • Bark (whitens, fights age spots),
  • creams with sun protection factor (SPF) 40;
• emulsions – experts recommend choosing ones with sun protection 50;
• oils:
• St. John's wort,
• roses,
• borage,
• immortelle.

Disease prevention

To avoid photoaging, you must follow the following rules:

• Stay in the sun for a limited time (in the morning before 11 a.m., in the evening after 4 p.m.).
• Cover exposed skin with clothing.
• Use sunscreen:
  • glasses,
  • skin products with filters or shielding effects.
• Include foods in your diet that help your body resist photoaging:
  • red and orange fruits and vegetables,
  • nuts,
  • sea ​​fish:
    • salmon,
    • mackerel,
    • herring
    • and other fish, especially fatty ones;
• cottage cheese,
• legumes, grains;
• green tea.

Complications

An undesirable consequence of skin exposure to ultraviolet radiation can be very rapid aging of the skin. In this case, even a young person may look wrinkled with thinning skin, which externally transfers him to another age category.

To prevent this from happening, it is necessary to take preventive measures to protect from the sun, and if photoaging does begin, contact a specialist to undergo treatment.

Forecast

The sooner you start treating skin for photoaging, the better the result. A systemic effect on the skin in order to restore its structure will certainly help stop aging and improve the condition of the skin.

A lot of useful information about the problem under consideration is given in this video:

It has long been noted that the skin of people who spend a lot of time in the sun begins to undergo negative changes much earlier. They manifest themselves in the form of increased keratinization (hyperkeratosis) and pigmentation, a network of fine wrinkles, increased dryness and sagging. With age, skin folds deepen, the thickness of the dermis gradually decreases, and the oval of the face is deformed. Such skin loses its protective properties, which significantly increases the likelihood of developing diseases, including cancer. A person looks older than his biological age, because photoaging is one of the main reasons for the early appearance of wrinkles.
Under the influence of sunlight, cell membranes are damaged, DNA cells, intercellular structures and collagen fibers responsible for skin elasticity are destroyed, pathologically altered elastin accumulates, the strength of blood vessels decreases, and the process of keratosis intensifies.
As a result of the accumulation of such defects, cells gradually lose the ability to perform their functions, stop dividing, degrade and die. The inability to retain moisture leads to dry skin, loss of former firmness and elasticity, and the appearance of fine wrinkles. In addition, the destructive effect of ultraviolet radiation causes dilation of capillaries, the appearance of spider veins and age spots.
It must be remembered that photoaging is usually observed in parallel with signs of age-related (chrono-) aging. However, there are special symptoms that are found almost exclusively in the first case and are not found in the second. This allows us to classify this condition as a separate nosological form, which is associated with a special pathogenetic mechanism for the development of photodamage.
The clinical signs of photoaging have already been described quite fully, but only relatively recently has light been shed on the molecular mechanisms responsible for macro- and microscopic tissue damage. The role of some cellular information transfer (transcription) factors in the pathogenesis of photoaging has been demonstrated, and it has also been found that mitochondrial DNA mutation plays an important role in the development of this pathology.
The process of skin photoaging is characterized by a number of clinical, histological and biochemical changes that, in contrast to age-related skin aging, have a special nature.
There are a number of synonyms for this process, which are also used when discussing this topic: “heliodermatitis”, “actinic dermatosis” and “premature skin aging”.

All people, regardless of age and gender, are susceptible to photoaging (the harmful effects of ultraviolet radiation). However, certain categories of people are more susceptible to it. These include:
- people with light skin;
- women during the period of hormonal changes (pregnancy and menopause), due to increased sensitivity to ultraviolet radiation;
- persons who often visit the solarium, take sunbathing, residents of southern cities, who are often in the sun.
According to its composition, solar radiation is divided into ultraviolet, visible light and infrared waves, perceived by humans as heat. It is the ultraviolet part of the spectrum that is responsible for premature aging of the skin. The ultraviolet part, in turn, is divided into three areas - A, B and C. It is the area “C” that has such a destructive effect that it threatens a person with death. The well-known ozone layer serves as protection against it.
UVA radiation causes a rapid change in skin color; it transforms in just a couple of hours. However, the duration of the resulting tan is short, since it is only a protective reaction of cells designed to stop the penetration of ultraviolet radiation into the deeper layers of the skin.
The long-lasting effect is caused by exposure to UVB rays; it lasts for many weeks and even months. Meanwhile, in addition to the beautiful brown tint of the skin, ultraviolet radiation of class “B” is accompanied by drying and roughening of the skin due to a more active keratinization process.
In this regard, it is worth noting that the spectrum of waves created by artificial sources is sometimes more harmful than sunlight. Visiting a solarium should be treated with caution, as it is not at all a safe alternative to natural tanning. After excessive enthusiasm for such procedures, all the signs of photoaging appear on the face, including significant roughening of the skin.

Photodamage is characterized by a number of quantitative and qualitative signs.

In the stratum corneum of the epidermis, signs of hyperkeratosis can be detected, but often the thickness of the epidermis remains unchanged.
Changes in the epidermis can also range from hypertrophy to atrophy. The basement membrane is thickened, reflecting possible damage to the basal keratinocytes. At the same time, along the basement membrane there is an uneven distribution of melanocyte processes of different sizes, accumulation of pigment and number of processes.
There is a relationship between the severity of damage and the strength-time of exposure to UV radiation. In other words, the formation of a vertical gradient of damage is noted. The most striking histological sign of this dependence is the destruction of elastin fibers, and the damaged fibers can occupy different parts of the dermis.
Another sign of “photopathology” in the dermis is the replacement of normal collagen fibers with collagen with clear damaged areas. This phenomenon is called "basophilic collagen degeneration."
More severe manifestations of photodamage include the expansion of areas of deposition of glycosaminoglycans responsible for the strength of cell membranes and fragmented elastin fibers, as well as dermal extracellular proteins - elastin.
Preventing photoaging is much easier than eliminating its consequences. The simplest preventive measures, carried out on a regular basis, prevent the formation of wrinkles, age spots, and increased dryness of the skin.
A feature of changes caused by exposure to UV radiation is their reversibility. The earlier the active fight against the signs of photoaging begins, the better results it can be achieved with the help of special procedures that stimulate regeneration processes, you can return the skin to its original blooming appearance. These include

Anna Margolina, Ph.D.

I. Prevention of premature skin aging
The annotations of many cosmetic products contain promises to eliminate wrinkles, increase skin firmness and elasticity, and slow down or even prevent aging. The considerable skepticism with which most doctors greet such statements is understandable. Aging is the gradual accumulation of defects in DNA molecules, the increasing disorganization of physiological processes in the cell, the accumulation of damage, which ultimately lead the body to death. There are many theories of aging, each of which to some extent explains the mechanism of breakdowns in cellular structures and their connection with external age-related changes. From all these theories a very disappointing conclusion follows - aging is inevitable. Despite the abundance of all kinds of healthy lifestyle programs, there is no recipe for eternal youth, as well as anti-aging cosmetics.

All these statements are true for true aging, however, the first wrinkles that appear on the skin of the face are a consequence not so much of this aging, which is universal for all tissues of the body, but of another process called photoaging .

Aging is different from aging
Age-related skin changes occur as a consequence of genetically programmed processes (implementation of the aging program), random events (failures and malfunctions in the system) and wear and tear of cellular structures as a result of exposure to harmful factors. In order to assess the significance of unfavorable environmental factors, it is enough to compare the skin on the face with the skin on closed areas of the body: age-related changes on open areas of the body appear much earlier than on areas protected by clothing.

Of course, the number of harmful factors that act on the skin and accelerate its aging is very large, so it is impossible to analyze the role of each of them. However, there is one factor that affects every person almost constantly - this is UV radiation. It is with this that, according to most scientists, the appearance of the first signs of aging in exposed areas of the skin is associated. It is believed that UV radiation initiates a degenerative process in the skin, as a result of which the skin becomes drier and rougher, gradually loses its tone, and wrinkles and age spots (solar lentigo) appear on it. Histologically, this is manifested by hyperkeratosis (thickening of the stratum corneum), atrophy of the epidermis, elastosis (degenerative changes in collagen with the accumulation of atypical elastin fibers), increased melanin content, the appearance of atypical melanocytes, and dilation of capillaries. These signs are absent in areas where the skin is mostly protected from exposure to UV radiation (for example, behind the ear).

With true aging, there is a thickening of the stratum corneum and atrophy of all other layers of the skin, including the dermis and subcutaneous fat, thinning of the capillary walls, atrophy of hair follicles, sebaceous and sweat glands. Changes caused by exposure to UV radiation are called photoaging, and changes that are a consequence of living years, respectively, are called chronoaging .

The face ages prematurely

Atrophic changes characteristic of aging skin are difficult to correct cosmetically. Even a surgeon with a scalpel, gel implants and gold threads is often powerless. Biostimulants, which women who want to turn back time usually rely on, give an effect only at first, until skin atrophy and extinction of vital processes have gone too far. There are a number of recommendations to delay the appearance of age-related changes, but all of them work only in combination with other measures (the so-called “healthy lifestyle”). However, by protecting the skin from the damaging effects of UV radiation, we can at least bring the rate of aging of the skin of the face and hands closer to the rate of aging of the skin on covered areas of the body.

Skin needs protection

The source of ultraviolet radiation, like other types of electromagnetic radiation (including visible light and heat), is the sun. A significant part of the UV radiation coming from the sun is blocked by the ozone layer, and some is attenuated by clouds, clothing, window glass and other obstacles (Fig. 1). The stratum corneum also blocks a certain percentage of UV radiation, but some of it still reaches the dermis.

Ultraviolet is radiation with wavelengths from 200 to 380 nm. As the wavelength increases, the energy of UV radiation decreases. The entire UV range is usually divided into the following areas:

*UV-C (200–280 nm) - completely blocked by the ozone layer.
* UV-B (280–320 nm) - partially blocked by the ozone layer, practically does not penetrate glass, is reflected by 70% by the stratum corneum, is attenuated by 20% when passing through the epidermis (less than 10% penetrates into the dermis).
*UV-A (320–380 nm) - is not blocked by the ozone layer, passes through glass and the stratum corneum. Due to absorption, reflection and scattering as it passes through the epidermis, only 20–30% of UVA penetrates into the dermis.

UVB is called the erythemal region of UV radiation. It is ultraviolet radiation in this range that causes erythema (redness of the skin or sunburn) and tanning. The dose of UV-B required to cause minimal visible erythema 24 hours after irradiation is called minimal erythemal dose(MED). This indicator is individual for different areas of the skin.

UVA does not cause sunburn (UVA MDR is a thousand times greater than UVB MDR), but this region of UV radiation is primarily responsible for the appearance of signs of photoaging, as well as UV-induced carcinogenesis.

So, UV radiation that hits the skin can be reflected by its surface, penetrate deep into it, or be absorbed by organic molecules. Only absorbed light has a damaging effect (the basic rule of photobiology is: no absorption - no effect). Therefore, knowing the absorption spectrum of organic molecules, it is possible to predict which of them will be damaged the most at a given wavelength.

When light quanta are absorbed, molecules enter an unstable excited state, which makes them more reactive. As a result, both completely stable compounds and free radicals and reactive oxygen species can be formed. Thus, UV radiation causes direct damage to biological molecules (proteins, nucleic acids), as well as mediated by free radicals (direct and indirect damaging effects) (Fig. 2).

Proteins and nucleic acids have a maximum absorption in the UV region, so they are the first to experience the harmful effects of UV radiation. Then, as a result of free radical reactions, lipid structures (lipid layers of the epidermis and cell membranes) are damaged. The reaction of lipid oxidation with the participation of free radicals (lipid peroxidation) has a chain, uncontrolled nature and leads to the formation of a large number of reactive oxygen species, lipid hydroperoxides and other reactive molecules. These molecules in turn react with proteins and nucleic acids, damaging them.

Degenerative changes in the skin under the influence of UV radiation may be associated with an increase in the activity of metalloproteases - enzymes that destroy the intercellular substance of the dermis. It has been experimentally shown that after skin irradiation with ultraviolet light, the activity of metalloproteases (collagenase, gelatinase, etc.) increases almost 4 times and remains at this level for a week after irradiation.

Another cause of tissue damage when exposed to UV radiation is inflammation. It occurs both as a result of peroxidation in cell membranes and as a result of the production of inflammatory cytokines by keratinocytes in response to UV radiation.

The insidiousness of tanning

UV radiation is harmful not only to human skin, but also to any living tissue. Scientists even believe that life on land was impossible until the ozone layer formed in the atmosphere, limiting the access of ultraviolet radiation to Earth. In the process of evolution, all living beings were forced, one way or another, to solve the problem of protection from the damaging effects of UV radiation. As a result, the main protective devices of different representatives of the animal and plant kingdoms turned out to be arranged in a similar way. Tissues that are exposed to UV radiation typically contain:

*pigments that absorb part of UV radiation;
*substances capable of intercepting free radicals and blocking reactions involving them (antioxidants);
*enzyme systems capable of restoring damaged cell structures.

In addition, the surface of the skin of most animals has additional protection from UV radiation - shell, mucus, scales, feathers, wool, etc.

Let's turn to the person. It seems that it is the worst protected from UV radiation of all. Of course, his skin contains antioxidants, but there are much fewer of them than in the skin of plants; in addition, human thin skin is devoid of feathers, wool, scales and does not produce protective mucus. For a long time, scientists believed that the main protector of human skin from UV radiation is melanin - a dark pigment produced by special skin cells, melanocytes. However, it turns out that melanin can be a very insidious defender.
People living in countries where the sun shines hot almost all year round have black or brown skin. This color is given to it by melanin, which melanocytes regularly supply to the cells of the epidermis. This process is best established in Negroids, which is why their skin is black or dark brown. In addition, the skin of Negroids is characterized by a higher content of antioxidants, high sebum secretion and greater thickness compared to Caucasians. All these features make the skin of Negroids quite resistant to the damaging effects of UV radiation.

Asians have lighter skin (brown or light brown), and its photoprotective ability is lower than that of Negroids. Therefore, they have to additionally protect their skin - wear long clothes made of thick fabric, cover their heads and faces from the sun (for example, women of the East traditionally wear a veil).

White people's skin contains little melanin. Moreover, according to modern scientific data, melanin in white-skinned people not only copes poorly with the role of protector, but can even enhance the damaging effects of UV radiation, generating free radicals. It would be fair to expect that white people would be especially careful with the sun, protecting themselves from it in every possible way, but this is far from the case. With amazing tenacity, they expose their unprotected skin to the sun, lie on the beach for hours, trying to be as naked as possible, and even go to sunbathe in countries with high levels of UV radiation. It is melanin that indulges these strange, from a biological point of view, actions, which is produced in the pale skin of Caucasians under the influence of UV radiation and colors it in beautiful golden, bronze or brown tones. Most people behave cautiously during the first days of their stay on the beach, afraid of getting sunburned, but then, confident that a “young” tan will reliably protect them from the harmful effects of the sun, they throw away all caution. Alas, despite numerous publications about the dangers of UV radiation, people’s attitude towards the sun has not changed significantly. The attractiveness of tanning and the belief in its protective properties outweigh all the arguments of scientists.

UV filters

The first thing to do to prevent photoaging is to reduce the number of photons reaching the skin. To do this, you should avoid the sun if possible and use sunscreen. We must not forget that not only UV radiation coming with the direct rays of the hot summer sun has a damaging effect, but also UV radiation reflected from the ground and surrounding objects, passing through clouds, water and even light clothing (Fig. 3 ). In addition, the amount of UV-A reaching the Earth, in contrast to the amount of UV-B, practically does not depend on the season, which means that even in the autumn-winter period, when the whole body is covered with warm clothes, the face continues to receive its portion of harmful rays. In this regard, some scientists recommend using cosmetics that contain UV filters every day, regardless of the time of year. Today, many companies include UV filters in decorative cosmetics, as well as day creams and makeup bases. Thus, from a means of decoration, makeup is gradually turning into a skin protector *.

* As is known, vitamin D is normally formed in skin irradiated with ultraviolet light. It is believed that with proper nutrition, the amount of vitamin D formed in the skin of the face and hands - almost always accessible to the sun - is quite enough to cover the deficiency. City dwellers who neglect health-improving walks and women who actively use cosmetics with UV filters should take care of a sufficient intake of vitamin D. - Note ed.

All UV filters are divided into chemical (or organic) filters that absorb radiation of a certain wavelength, and physical (inorganic) filters or screens that contain particles that scatter, reflect and absorb UV radiation.

Organic UV filters include:
*UVB filters - cinnamates, benzophenone, para-aminobenzoic acid (PABA) and its derivatives, salicylates, camphor derivatives, etc.
*UV-A filters - dibenzoylmethane, benzophenone, camphor derivatives, etc.
*Natural sunscreens - aloe and chamomile extracts, caffeic acid, butyros perma oil (called “shea” or “karite”), 1,3-b-glucans, etc.

Titanium dioxide (TiO 2), zinc oxide (ZnO), iron oxides (Fe 2 O 3, Fe 3 O 4), etc. are used as inorganic UV filters.

It is not easy for a consumer to understand sunscreens, since the same UV filter has not only a chemical name, but also a number of trade names. For example, benzophenone-3 ( ben*zophenone-3) can be called Oxibenzone, Escalol 567, Eusolex, Rhodialux, Spectrasorb UV-9, Uvinul M-40 (and another filter is encrypted under the name Uvinul N-539 - octocrylene ( octocrylene)).

Even the solar protection factor ( sun protection factor, SPF) indicated on the label can be confusing. SPF is the ratio of the MED of skin protected by a UV filter to the MED of unprotected skin. Because UVA damage is not associated with erythema, SPF does not provide any information about how well a given sunscreen protects skin from UVA radiation. In addition, the effectiveness of protection depends on the thickness of the layer of sunscreen on the skin, on the speed at which this product is washed off with sweat and water, on skin type, etc.

Another problem with sunscreens is the frequent allergic reactions they cause. Moreover, allergenicity increases in direct proportion to the concentration of UV filters (in other words, the higher the degree of protection, the higher the risk of allergic reactions). This makes it quite difficult for people with sensitive skin to implement the idea of ​​using sunscreen every day. However, UV filters are not the only possible way to protect the skin from photoaging.

Antioxidants in the skin

During the process of evolution, protective mechanisms have been formed in the skin to reduce the damaging effects of UV radiation. Some of them work on the same principle as cosmetic sunscreens, that is, they reduce the number of photons reaching vulnerable skin structures. Substances that absorb UV radiation (melanin, urocanic acid) act as chemical UV filters here. The role of a physical filter is played by the stratum corneum, which thickens in response to intense UV radiation.

However, direct damage to biological tissue by UV radiation is only partly responsible for photoaging. A much greater contribution to this process is made by reactions involving free radicals, formed both as a result of the direct action of UV radiation (Fig. 4), and accompanying the inflammatory reaction caused by it. Therefore, antioxidants play an important role in protecting the skin from the damaging effects of UV radiation - substances that neutralize free radicals and block reactions involving them.

To protect against the damaging effects of UV radiation, a reliable antioxidant system has been formed in the skin. Already on the surface of the skin, a significant amount of fat-soluble antioxidants is found, which continuously enter here along with sebum - a-tocopherol, b-carotene, squalene. A decrease in the level of a-tocopherol in the stratum corneum is considered the earliest sign of oxidative stress in the skin. The main task of antioxidants on the surface of the skin is to protect keratin and epidermal lipids from free radical oxidation.

Living cells of the epidermis contain a whole range of antioxidants, including enzymatic and non-enzymatic. Enzymatic antioxidants include superoxide dismutase (SOD), catalase, and glutathione peroxidase. SOD fights reactive oxygen species by catalyzing the reaction of two oxygen superoxide anions (O 2 – ) into hydrogen peroxide (HOOH). Hydrogen peroxide is also a toxic compound, but it does not have time to cause harm, because the enzyme catalase immediately converts hydrogen peroxide into water and oxygen.

The membranes of keratinocytes contain a lot of a-tocopherol, which intercepts free radicals and blocks lipid peroxidation reactions. The cytoplasm of cells contains ascorbic acid, which is a reducing agent, including for a-tocopherol. Ascorbic acid itself is reduced in the glutathione peroxidase reaction. Thus, antioxidants work together to restore each other.

In addition to the listed compounds, female sex hormones, sulfur-containing amino acids, soluble melanin precursors, and melatonin also have antioxidant properties. Since the epidermis most often becomes the arena for free radical reactions, the concentration of almost all antioxidants in it is 24–90% higher compared to the dermis.

Such a powerful antioxidant defense system still has vulnerabilities. Antioxidants of protein nature, like all other proteins, are damaged when exposed to UV radiation, and their activity decreases until complete inactivation. As for other antioxidants, they are consumed (oxidized) in the process of fighting free radicals, after which they need to be restored. If antioxidants are not restored quickly enough, then at some point a flood of free radicals can overwhelm skin cells.

You can support the skin's natural antioxidant system in its fight against free radicals by using cosmetics containing antioxidants.

Antioxidants in cosmetics

Antioxidants in cosmetics, like antioxidants in the skin, are divided into fat-soluble (lipophilic) and water-soluble (hydrophilic). The former are introduced into the oil phase of the cosmetic product, and the latter into the aqueous phase.

Of the fat-soluble antioxidants in cosmetics, a-tocopherol, carotenoids, squalene, and ubiquinone are most often used. In addition to traditional vitamin C, plant polyphenols (flavonoids) are used as water-soluble antioxidants. Due to the growing popularity of flavonoids, let's look at them in more detail.

Flavonoids are a chemically heterogeneous group of polyphenolic compounds that are widely distributed in the plant world (Fig. 5).

Numerous studies have shown that flavonoids have the ability to intercept free radicals, inhibit lipid peroxidation reactions (at any stage), and bind metal ions.

In cosmetics, bio flavonoids (flavonoids with P-vitamin activity) are often used as antioxidants, anti-inflammatory agents, agents that strengthen blood vessels and improve microcirculation. To do this, extracts of green tea (Camellia sinensis), grape seeds (Vitis vinifera), maritime pine bark (Pinus pinaster), ginkgo (Ginkgo biloba), Roman chamomile (Anthemis nobilis), calendula (Calendula officinalis), blue cornflower are added to the recipes. (Centaurea cyanus) and other medicinal plants rich in bioflavonoids.
Green tea extract contains about 20–30% lifephenols, among which the most are catechins. Catechins have a number of valuable properties from a cosmetological point of view. They are effective traps of reactive oxygen species (superoxide and peroxide), block the reaction of lipid peroxidation, protect cells from the action of mutagens, and also have a direct anti-inflammatory effect, affecting the metabolism of arachidonic acid. The pronounced anti-inflammatory and soothing effect of green tea extract is widely used in daytime and sunscreen products, pre-peel and post-peel lotions, anti-acne lotions, etc.

Grape seed extract contains mainly anthocyanins and proanthocyanidins. These substances have antioxidant properties, are able to bind metal ions, inhibit a number of enzymes that are usually activated by UV irradiation and destroy the intercellular substance of the dermis (elastase, collagenase, hyaluronidase). In addition, the bioflavonoids rutin and quercetin (flavonols), contained in grape seed extract, help strengthen the walls of blood vessels and stimulate collagen synthesis.

Ginkgo extract contains a large amount of rutin and quercetin, which have a beneficial effect on microcirculation and are powerful antioxidants. In addition, ginkgo extract contains many other unique biologically active substances.

Reactions involving free radicals initiated by UV radiation unfold in the skin quite quickly, so it is very important to provide reliable protection before the damaging factor begins to act. That is why antioxidants, as well as UV filters, have become an almost obligatory component of day and sunscreen creams, as well as decorative cosmetics. (However, here, as in everything, it is very important to observe moderation, since excess antioxidants can have a pro-oxidant effect).
By constantly using cosmetics containing antioxidants and avoiding sunbathing, you can significantly slow down the rate of skin aging. Alas, for many modern women such recommendations are somewhat belated, since their faces are already marked with wrinkles and age spots - a consequence of an unbridled fascination with the sun in their youth. In this case, the skin needs not only protection, but also treatment.

II. Fighting photoaging

The theory of photoaging appeared in the mid-80s and soon became a sensation. What was always considered irreversible age-related skin changes, the fight against which is the lot of madmen or charlatans, turned out to be something like a disease that can be treated. And already in 1986, the works of A. M. Kligman appeared, who demonstrated the ability of trans-retinoic acid (tretinoin) preparations to eliminate many signs of photoaging and restore normal skin structure. Following Kligman’s work, a stream of publications devoted to the treatment of photoaging poured into the pages of medical journals. Once tretinoin's ability to reverse the signs of aging was confirmed, the attention of cosmetics manufacturers turned to both tretinoin and other compounds with similar effects (retinoids). Retinoids, which were previously used in dermatological practice for the treatment of acne and some other skin diseases accompanied by dyskeratosis (for example, ichthyosis), crossed the chasm separating drugs from cosmetics and opened the era of cosmeceuticals.

Retinoids in cosmetics against photoaging

In the work of A. M. Kligman et al., published in 1986, it was shown that with daily application of 0.05% tretinoin to the skin of the face and elbow, the skin gradually replaces the atrophic epidermis with normal, eliminates tissue dysplasia, reduces the thickness of the stratum corneum and its compaction, a decrease in the number of melanin granules and their more uniform distribution in the epidermis, the formation of new collagen fibers in the papillary layer of the dermis, the growth of new capillaries. In 1989 Goldfarb et al. published the results of clinical trials (conducted both open-label and double-blind), which also showed the effectiveness of 0.1% tretinoin in the treatment of photoaging. During treatment, many patients experienced dermatitis, but most subjects rated the discomfort as quite tolerable. Already in 1992, Kligman wrote that since his first publication on the use of tretinoin for the treatment of photoaging, the ability of retinoids to restore normal structure to skin damaged by UV radiation has been fully confirmed by numerous controlled clinical trials conducted in a double-blind manner. both in the USA and Europe.

Now retinoids remain the main weapon of cosmetologists in the fight against photoaging. And laboratories continue to test new formulations that could reduce the irritant potential of tretinoin and make treatment more comfortable for patients. Preparations have been developed based on trans-retinoic acid derivatives (retinyl palmitate, retinyl acetate), which have a milder effect than tretinoin. To reduce the irritating effect of retinoids, extracts of green tea, grape seeds, pine bark, chamomile, calendula, seaweed, etc. are added to cosmetics.

Retinoid-based preparations are usually included in professional cosmetic lines, where they are used in a comprehensive program to combat photoaging. Another important component of this program is skin exfoliation - peeling.

Peeling - superficial, medium, deep

It has long been known that controlled damage to the top layer of skin can produce a rejuvenating effect. In response to damage, regenerative processes are activated, and as a result, not only wound healing is observed, but also a general improvement in the structure of aging skin. Therefore, along with retinoids, peeling with phenol (deep) and trichloroacetic acid (medium) was used (and is still used) to treat photoaging. When carried out correctly, phenol peeling gives a good rejuvenating effect. However, this requires very high qualifications of a specialist, since the depth of penetration of phenol is difficult to control. Complications of phenol peeling can include permanent hypopigmentation and scars. Some patients may experience complications from the cardiovascular system.

An alternative to phenol are concentrated preparations of a-hydroxy acids (AHAs). Here, glycolic acid is most often used in concentrations of 50–70%. It is believed that it acts not so much as an exfoliating agent, but rather as a direct stimulator of the synthesis of the intercellular substance of the dermis.

Exfoliation of the skin can be carried out using hardware methods - dermabrasion and laser resurfacing. Carbon dioxide lasers (CO 2 lasers) and erbium lasers have gained particular popularity here. Laser radiation is absorbed by water contained in the skin, its energy turns into heat, as a result of which the epidermis almost instantly evaporates (or vaporizes, from the English. vapor- steam). In the area affected by the laser beam, not only vaporization is observed, but also more or less deep coagulation of tissue affecting the dermis. Gradually, a new one appears in place of the evaporated epidermis, and increased synthesis of collagen fibers occurs in the coagulation zone. If the coagulation zone is too extensive, normal regeneration becomes impossible and scars form on the skin. Laser resurfacing is an effective but expensive method of treating photoaging. This procedure is carried out only in medical institutions.

Whitening products

One of the very noticeable and therefore distressing signs of photoaging is pigment spots - solar lentigo. To eliminate lentigo, 2–4% hydroquinone preparations are used, which are applied exactly to the area of ​​the spot, kojic acid preparations, ascorbic acid (magnesium ascorbyl phosphate). Concentrated AHAs (glycolic, tartaric, lemon) give a good effect. For multiple age spots that do not respond well to conservative treatment, deep exfoliation of the skin is used (phenolic peeling, laser resurfacing, dermabrasion)

Conclusion

UV radiation affecting the skin damages proteins, cell membrane lipids and nucleic acids. Gradually accumulating, these damages cause degenerative changes in the epidermis and intercellular substance of the dermis. Outwardly, this resembles age-related changes in the skin - dryness, decreased tone, the appearance of wrinkles, dilated capillaries and age spots. However, true aging - chronoaging - begins much later, which can be judged by comparing the skin of the face with the skin of areas of the body protected from the sun. To protect your skin from the damaging effects of UV radiation, it is recommended to use sunscreens and antioxidants.

Photoaging, unlike chronoaging, is largely reversible. Skin, like any living tissue, can not only protect itself from damage, but also restore damaged structures, striving to return to its original harmony. By supporting and stimulating repair systems, you can significantly improve the appearance of skin damaged by UV radiation and achieve visible rejuvenation.

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