Anti-age capabilities: correction and control

The condition of the skin is one of the most important signs of age. Skin aging is an irreversible process of development of specific morphological, biochemical, biophysical changes in the skin, which accompanies involutionary processes throughout the body. However, unlike other organs and systems, the age of the skin is determined not only by the individual program of genetic aging (the so-called internal, chronological age), but also by the influence of such external factors as the intensity of insolation, smoking, lifestyle (the so-called external age, or photoaging).

Proving the effectiveness of anti-aging products along with the intrinsic mechanisms of aging and the effects of socioeconomic factors has become a major focus in skin research. On the European market, confirmation of the effectiveness of anti-age products (in particular, anti-aging products, drugs that reduce the severity of wrinkles) serves not only marketing purposes, but is also an integral part of the registration of cosmetic products.

Clinical characteristics of skin aging

Signs corresponding to chronological (intrinsic) aging include:

• fine wrinkles;
• thinning and translucency of the skin;
• reduction of subcutaneous fat with loss of volume, sagging skin;
• benign changes on the skin (seborrheic keratosis, simple angiomas, etc.).

Clinical signs that determine external aging:

• deep wrinkles;
• uneven pigmentation (freckles, lentigo, “speckled” pigmentation, areas of hypopigmentation);
• decreased elasticity and severe lethargy;
• xerosis;
• vascular lesions (telangiectasia, senile purpura), neoplasms (actinic keratosis, Favre-Rakuchot syndrome, squamous cell carcinoma, basal cell carcinoma, etc.).

The Glogau scale is widely used to determine the degree of skin photoaging (Table 1). These signs are recorded and compared using the following non-invasive methods:

• high-resolution digital photo in compliance with the basic rules of photo documentation;
• visioscopy as a non-contact method for assessing microrelief using polarized light, which allows recording images of skin texture and wrinkles;
• 3D modeling of the skin surface;
• profilometry – using the silicone replica method allows for direct measurements of wrinkles and skin texture;
• corneosurfometry – assessment of damage to the stratum corneum;
• confocal microscopy, which allows non-invasive high-resolution visualization of age-related changes in the deep layers of the skin.

Table 1. Scale for measuring the degree of photoaging according to Glogau

Histolonic signs of skin aging

Internal (chronological) aging causes minor changes in the thickness of the epidermis and the shape of keratinocytes, a decrease in the number of melanocytes and Langerhans cells, and a weakening of the dermal-epidermal connections. In this case, no changes in the stratum corneum are observed.

At the level of the dermis, with chronological aging, atrophic changes in connective tissue, a decrease in the number of fibroblasts, a decrease in the number of blood vessels in the dermis with a reduction in the number of capillary loops, a decrease in the number of nerve endings and the neuroreceptor apparatus of the skin are observed.

External aging at the level of the epidermis causes compaction of the stratum corneum and granular layer, a decrease in the thickness of the epidermis, a decrease in mucin content, an increase in the number of melanosomes in basal keratinocytes, a disturbance in the shape and size of cells and nuclei, and a weakening of the dermal-epidermal connections.

At the level of the dermis, homogenization of connective tissue, a decrease in the amount of collagen types I, III and VII, elastosis of the dermis, a decrease in the amount of glycosaminoglycans, and replacement of normal collagen fibers with collagen with clear basophilic areas are detected.

Histological data are assessed in vitro by electron microscopy, which due to the invasiveness of the procedure is not widely used.

Functional signs of skin aging

Sometimes it is stated that transepidermal moisture loss increases with age, and this in turn can cause dry skin. However, it is not. The barrier functions of the skin, as a rule, continue to operate both with chronological aging and with photodamage to the skin. However, in both cases there is a slowdown in the recovery of skin barrier function after damage to the epidermal barrier.

The main functional signs of skin aging are a decrease in hydration of the stratum corneum without a specific localization (with chronological aging) or in places of increased insolation (with photodamage), an increase in pH levels (regardless of the location in both cases), and a decrease in vasorelaxation of skin capillaries with a genetic type. With photoaging, there is also a decrease in the photoluminescent properties of the skin in relation to undamaged areas, in addition, the level of skin elasticity decreases, especially in areas of photodamage.

Based on this, the main functional methods used in diagnosing skin aging are:

• measurement of transepidermal water loss (TEWL);
• measurement of the moisture content of the stratum corneum - corneometry;
• measurement of the mechanical properties of the skin, primarily elasticity, cutometry.

Measuring transepidermal water loss

The more damaged the epidermal barrier is, the more water evaporates. The TEWL indicator is currently the most informative for assessing the intercellular lipid matrix and is measured using tevametry - a method for assessing the rate of evaporation of liquid from the surface of the skin. The intercellular lipid matrix is formed in the granular layer of the epidermis and provides the protective function of the skin. The main moisture loss occurs through intercellular hydrophilic channels of the lipid matrix. The alternation of hydrophilic and lipid layers of the intercellular matrix keeps transepidermal water loss (TEWL) at a constant level.

There is evidence that with aging, the level of transepidermal moisture loss not only does not increase, but even tends to decrease. However, if the epidermal barrier is damaged, the restoration of the moisture-retaining function slows down, which must be remembered when carrying out procedures associated with chemical and physical damage to the skin (primarily this applies to peelings).

When a TEWL sensor is installed on the skin, a density gradient of water vapor evaporating from the surface is established in its cavity. This gradient is measured using two pairs of sensors located in the sensor cavity (one pair measures temperature, the other measures relative humidity).

Measuring the moisture content of the stratum corneum - corneometry

The water content in the stratum corneum largely depends on its water-holding capacity and the condition of the hydrolipid mantle of the skin. Dry skin develops wrinkles earlier and reacts more strongly to aggressive environmental factors. People with dry skin often complain of an unpleasant feeling of tightness, flaking and itching. After 65 years, dry skin is observed in 80% of cases.

To objectively measure skin dryness, a corneometry method was developed, which was patented in 1980 and is still considered the most reliable and accurate method for assessing the hydration of the stratum corneum of the skin.

The principle of operation of the corneometer is based on assessing the dielectric constant of the surface layers of the skin. Any changes in the dielectric constant as a result of fluctuations in water content lead to a change in the capacitive characteristics of the sensor's measuring system.

Unlike the impedance measurement method, which requires direct contact of electrodes with the skin, the measuring part of the corneometer is separated from the skin by thin glass, which prevents direct contact of the electrical conductor with the skin. On the one hand, this makes the method safe for human health, on the other hand, it is more objective, since the measurements depend only on the water content in the stratum corneum, and the salts secreted by the sweat glands have virtually no effect on the measurements.

Elasticity measurement

One of the main symptoms of aging is also a decrease in skin elasticity. First of all, this is due to the “wear and tear” of the connective tissue. Measuring skin elasticity is often called determining its biological age.

The mechanical properties of the skin depend not only on the ratio of different types of fibers, but also on the fluid content in the dermis. An increase in fluid in the pores of the connective tissue framework causes tension in collagen and elastin fibers, which leads to an increase in skin firmness and elasticity. With age, the ability of connective tissue to retain water in the dermis decreases.

To determine elasticity, the so-called pinch method was previously used. Due to the fact that this method is very difficult to quantify elasticity (which is important for determining biological age), objective methods for measuring this parameter have been developed. Today, the cutometry method is considered the most accurate and reproducible.

In this case, the measurement is based on the well-known suction method. During measurement, the skin is sucked into the sensor opening under a negative pressure of 400 mbar. Then the negative pressure is reset to 0, and the skin gradually returns to its original state. The higher the elasticity, the faster it returns to its original state after the pressure is released. Skin elasticity E is estimated as a percentage and is calculated using the formula:

(ab) x 100% = E (%)

where a is the maximum amplitude of skin suction, b is the height of the skin tubercle after relaxation.

In a cutometry sensor, the height of the skin tubercle is assessed using a special optical system. This method measures the height of a small area of skin as it is sucked into the sensor cavity. The more elastic the skin, the less it is absorbed into the sensor cavity. The more elastic the skin, the faster it will return to its original state. In this case, by elasticity we mean the ability of the skin to resist deformation, for example, stretching, and by elasticity we mean the ability of the skin to restore its shape after deformation (for example, after a pinch).

The main framework of connective tissue is collagen, and among all components of the dermis it has the greatest elasticity. As the amount of collagen in the dermis increases with age, the mechanical strength of the dermis increases, and the elasticity of the skin increases. However, the elasticity of the skin, which is determined by the state of elastin fibers, which can not only stretch greatly, but also quickly return to their original state, decreases. The mechanical properties of the skin are determined not only by the ratio of collagen and elastin, but also by the fluid content in the dermis. It has been shown that an increase in fluid in the pores of the connective tissue framework causes tension in collagen and elastin fibers, and this in turn leads to an increase in skin firmness and elasticity.

conclusions

Thus, when prescribing anti-aging procedures, it is necessary first of all to take into account the predominance of one or another type of skin aging. With photodamage (especially in the initial stages), many changes are reversible. Cosmetic care gives a quick and long-lasting effect.

It is very important to convince the patient to avoid prolonged sun exposure and limit visits to solariums. At the same time, with chronological aging, methods of prevention and correction are limited. Effective methods include biorevitalization, contour plastic surgery, laser, chemical and mechanical abrasion, and plastic surgery. Hormone replacement therapy is often prescribed to slow biological aging.

Having a wide range of anti-age procedures in his arsenal, a cosmetologist can choose an individual care program. Evaluation of the effectiveness of cosmetic care must be carried out in accordance with the following standards:

• photo documentation before and after care programs;
• recording the main functional parameters: TEWL, corneometry, cutometry - both at the beginning and during the course of cosmetic therapy.

Knowledge of the mechanism of action of certain products and methods on aging skin allows you to make the right choice of both cosmetic lines and equipment. We recommend paying attention to the clinical studies conducted, especially with innovative methods and means. Claims of effectiveness must be based on evidence. Beautiful legends about the miracles of rejuvenation are intended for clients, not specialists.

The cure for Makropoulos has not yet been found, but we can “slow down time.” Therefore, anti-age procedures are the most in demand today in the cosmetic services market. A wide range of anti-aging procedures and products allows you to choose the optimal care program, taking into account the price/effect/duration of effect/safety ratio and always based on evidence-based cosmetology data!

This article is part of the special project Global anti-aging

You can read all the articles on this topic:

SPECIAL PROJECT. Global anti-aging

Literature:

Tatyana Momot, certified consultant Courage+Khazaka electronic, director of Laboratory SK LLC (Kyiv)

Les Nouvelles Esthetiques Ukraine, No. 6 (70), 2011-2012, pp. 92-95