The scenario of skin aging

The contemporary society is in common particular about being active all the time; general exhaustion and the signs of aging are not the things we want the others to notice.

Our body ages as a unit – the genetically programmed processes lead to organic changes (e.g. atherosclerotic veins), as well as functional changes (e.g. lowered immunity against infections). The skin is an organ on which we can study the process of aging very well. One does not want to submit himself to the natural regularities. For this reason, dermatology, corrective dermatology and cosmetology seek new, safe and widely available methods to slow down the process of aging or even reverse the ongoing changes.

 

Epidermis

At older age, the epidermis starts to thin away. The stratum corneum (horny layer) has a reduced water content and becomes easily penetrable for chemical substances. The epidermal cells begin to lose their capability to regenerate and their life span shortens. Matrixes of melanocytes occur in the basal layer. These cells produce pigment and this leads to the formation of brown and yellowish stains. On the contrary, melanocytes decrease on other parts of epidermis, clinically manifested as white stains – guttate hypomelanosis. The line between the epidermis and corium merges and stretches, losing its firmness.

Corium
The cells existing in the corium are mainly fibroblasts. They are very important for the synthesis of fibers. Collagen fibers have a fundamental relevance for skin firmness. At old age, their number reduces and so does their firmness and mechanical resistance; their organization changes. Because of old age and also the UV radiation, the elastic fibers degenerate, thicken and shorten. Within the network of fibers, there is a basic substance, a gelatinous mass containing glycosaminoglycanes and hyaluronate acid which are water binding. This system assures the transport of nutrients into the skin.

Subdermal adipose tissue
With atrophy of the connective tissue, deep dermal folds start to form. Cellulite occurs at overall weight growth. It shows up especially on the thighs and sides. The skin gathers and the phenomenon of “orange peel” emerges

The blood vessels and corium in the subcutis have widened pits; they are less elastic and split easily.

Hair
The density of hair follicles reduces, the growth phase shortens; the hair is finer and more tenuous and becomes thin in the zone under the armpits and around the genitals. On the contrary, the eyebrows and the hair in the ears and nose can boost – this refers especially to men. Because of the influence of male sex hormone, unwanted hair can occur on woman’s upper lip or on the beard. Trichopoliosis is caused by the diminution of melanocytes (the cells producing pigment) or their disturbed function.

Nails
Their growth is slowed down; the glare and clarity disappear and longitudinal creases start to occur. The toenails usually get horny.

Sebacious and sudoriferous glands
Their activity decreases with growing age. Moreover, hypertrophy of sebaceous glands can occur on the face.

Slackness of the skin and wrinkle formation
There are many factors influencing the wrinkle formation. Their presence in certain locations underlies the action of mimic muscles. Another unwanted manifestation of the relentless effect of time is the overall slackness of the skin. Because of the degenerative processes in the connective tissue of the corium (diminution of collagen tissues and water), the cutaneous turgor (tension) reduces and elasticity (we can imagine elasticity as a plastic ball – it deforms under pressure and if the pressure stops, the ball returns to its previous shape). On the contrary, the plasticity enhances (the existing deformation lasts, e.g. thanks to the action of mimic muscles; the change responds to the modeling of plasticine). At the same time, the surface of the skin dries out, it loses its glare and changes of pigment occur. The surface of the skin gets rougher in general. Wrinkles caused by simple senile atrophy disappear after stretching the skin. Such negative changes take place much faster on unprotected skin – exposed to UV radiation. In professional terminology, these changes are called solar elastosis. Wrinkles formed in this way do not disappear after stretching the skin. The process of female skin aging is also influenced during the hormonal changes within menopause.

There are other visible cutaneous changes apart from the wrinkles, which signalize the growing age – mainly the movement of pigment (reduction or enhancement), the occurrence of widened vessels, dryness of the skin and the already mentioned changes of hair and nails.

Methods used for skin rejuvenation 

We can divide them into two groups: invasive (plastic surgery operations – standard or laser, skin implantations, application of botulinum toxin, chemical peeling) and noninvasive. Both methods include external, perhaps even internal application of active substances which are aimed at restoring the already existing damages, eventually even prevent them. This includes photoprotection, whitening remedies, retinoids, antioxidants, betacaroten, flavonoids as well as hormonal substitute treatment of women after menopause. In terms of early skin aging prevention, it is entirely essential to protect the skin against the influence of UV radiation since early age.

Nové trendy při vývoji kosmeceutických prostředků

In recent years, we ever more come into contact with cosmetic products containing active substances based on peptides. They are substances, which intervene in the physiologic processes of the skin on different levels. Besides gravitation, it is also the mimicry which is responsible for wrinkle formation. The transfer of pertubation to the neuro-muscular platelet is essential for the activity of muscles. One of the used active peptides is the hexapeptide ARGIRLIN – it represents the substitute structure which blocks the place where the transferring agent acts – the pertubation transfer does not actualize, the muscular tissue does not contract and therefore the wrinkle does not form. Other substances participating in the pertubation transfer can be blocked on different levels of this process, on the basis of a detailed study of the physiologic pertubation transfer and muscular tissue contraction. Their cooperation causes the enhanced effect of the final product. 
The restoration of movement of the cell functions represents a new approach to the renovation of cutaneous structures. Matrikines are short fragments of peptides and have the same series of aminoacids as the resoluble peptides which form physiologically in the tissue during the wound healing. They are messengers capable of regulating the cell activity by acting on their specific receptors. They are referred to as the feedback peptides. They activate certain genes which participate in the process of restoration of the extracellular substance and cell reproduction. During their presence in the epidermis, the activity of the fibroblasts is stimulated and so is the synthesis of collagen. This leads to a repeated strain of the matrix and to a better connection on the dermo-epidermal junction. Other substances are formed: glycosaminoglycanes and hyaluronate acid. A similar effect has the commonly used retinol, though it can evoke inflammation and irritation. The activity of matrikines is far more complex; they can replace the collagen injections and vitamin C. Young skin contains collagen fibers, which form a network. The apertures of this network are filled with proteoglycanes and glycosaminoglycanes. With the participation of hyaluronate acid, these substances compose a waterlogged gel – this ensures the circulation of the hydro-soluble substances. With aging, the amount of collagen reduces – the substitution of fragmented fibers of elastin. The lack of water induces flatness, failed skin and insufficient exchange of substances.

Enzymes accelerating the keratolysis (the disturbance of keratin) represent another novelty in terms of introducing new cosmeceuticals. They ensure the acceleration of desquamation – the cell peeling off and regeneration – without irritating the skin. (Result: cell restoration – brightening up of the face and youthful appearance).

Ingredients with anti-inflammatory and vein-toning effects are used for treatment of enlarged veins.

The multiplication of pigment is another manifestation of aging. Products used for tender and effective whitening work on the basis of tyrosinase enzyme inhibition, which is necessary for melanin formation. One of the ingredients used for skin whitening is hydrochinon. This substance is a false substratum for tyrosinase. It may evoke irritation, sometimes even contact allergic reaction; it is regarded as cancerogene. It is not faculty in medical and cosmetic remedies in our country. Arbutin and harounoside act similarly to hydrochonin, but with more care

It is usual, that active substances are examined for cosmetic industry, analogous to pharmaceuticals. Optimal concentrations of the final product as well as the best environment for biologic availability of ingredients are determined. The bearing ground for cosmetic products is very important for establishment of transfer of the resident active substances inside the skin. They contain entirely new transport systems which ensure the formation of a thin functional layer on molecular level. Therefore, the substance which is the carrier of the declared effect penetrates into the keratin layer in the best way. Liposomes have served as the transport system to transfer the active ingredients to the target structures for a long time. Their ever more developing production technologies now enable us to develop PMLs (Plurilamellar Multivesicular Liposomes) – a sort of super-liposomes containing various active substances – inside the liposome vacuoles, the fat-soluble substances are protected by a phospholipids cover; on the contrary, there are water-soluble substances between the two layers. This way, it is possible to transfer e.g. the Sodium Hyaluronate in the epidermis. Na-Hyaluronate plays a major role in moisture retention in epidermis. Sufficient hydration is a condition for elasticity and flexibility of the skin as well as for adequate exchange of the substances.

Modern cosmetology works on a strict academic level. It examines the physiology and immunologic processes of both, the healthy as well as the injured skin. At the same time, irritability of the new substances and other possible negative effects on the vivid tissue are determined. 

 MUDr. Andrea Vocilková