Melanogynez

Melanogenesis is one of the complex phenomena of the organism’s adaptation to the environment. Mechanisms of melanin synthesis and regulation of pigment cell activity have been in the focus of attention of specialists in various fields of knowledge in recent years. This is due to the initiative of the International Union against Cancer, which has called to focus the efforts of researchers on studying pigment cells as the progenitor of the most malignant tumor in humans and animals – melanoma.

Two international conferences have been devoted to consideration of various aspects of pigment cell activity and melanin synthesis both in norm and pathology, and more than 1600 scientific works have been published.

Meanwhile, little attention has been given to the dermatological aspects of this problem, although dermatologists have long been interested in melanogenesis and have made significant contributions to understanding the chemistry of melanin synthesis and the pathogenesis of pigmentation disorders.
The range of diseases involving pigment cells is large.

Melanogenesis is the process of melanin formation from tyrosine via the enzymes tyrosinase and DOPA oxidase. Melanosomes, granules filled with melanin, are transported to keratinocytes through branching offshoots by phagocytosis. Melanocytes are located among the cells of the basal layer and have several outgrowths that can extend up to 100 μm from the cell body to the membranes of individual keratinocytes. The distribution of melanocytes and the way they branch normally is such that almost every cell of the basal layer contacts their terminal parts. There is also contact of melanocyte outgrowths with each other. Melanosome formation and synthesis of melanin pigment in them are independent processes, because albino and vitiligo patients have melanocytes with melanosomes that do not contain premelanin and melanin in the epidermis. Melanin biosynthesis begins on the inner membranes of melanosomes. Under the action of tyrosinase (tyrosine hydrolase), tyrosine is converted into L-DOPA-quinone (L-dioxyphenylalanine).

Melanocytes are a permanent cellular ingredient of mammalian epidermis. They are located among the basal cells of the malpighian layer. Each melanocyte consists of a pericarion, which is elongated and from it the primary branches branch off and head upwards between the cells of the epidermal thorny layer. Each end of the melanocyte branch is a sharply DOPA-positive button. The pigment is also found in keratinocytes; it is transferred to them by phagocytosis.

Each melanocyte secretes melanin granules into a limited number of neighboring epidermal cells. This partnership of the melanocyte with the nearest epidermal cells is considered in functional unity and is known as the epidermal melanin unit of the epidermis.
Thus, according to modern concepts, melanocytes are highly specialized cells of the epidermis. These cells are the only ones capable of producing melanin pigment, which they, in turn, transfer to a certain group of malpighian cells, forming together with them a complex functional unit.
The main function of melanin is to regulate the amount of ultraviolet (UV) radiation penetrating the skin. The absorption spectrum of melanin covers the entire range of visible light and the UV range. When absorbing quanta of light, melanin converts part of the energy into heat and part of it is used for photochemical reactions. Melanin and its precursors can oxidize, polymerize, and produce free oxygen radicals, which damage the cell.
A spot of pigmentation is an area of excessive accumulation of melanin, a special pigment found in different layers of the epidermis. When it is deposited in the top layer of the skin, small spots (such as freckles) form. They can range in color from light yellow to brown and, in most cases, do not give their owner much trouble or worry.

Hyperpigmentations that are deposited in deeper layers of the epidermis look completely different – dark brown spots appear on the surface of the skin (they may rise above the surface of the skin).
Patches of pigmentation can appear both in young girls and in women over 50. As a rule, their appearance is more likely over the age of 35-40. In isolated cases, they disappear spontaneously, much more often it takes a lot of effort to get rid of them.

Doctors distinguish the following types of pigmentation:

• freckles;
• chloasma;
• lentigines;
• birthmarks (moles).
• Causes of increased melanin synthesis:

Hereditary (genetic) factor. It is the result of genetic predisposition and is usually diagnosed at birth. Severe pigmentation can be treated with modern surgical techniques (e.g., laser resurfacing);
Hormonal changes in the body. Such pigmentation may be quite noticeable and is a consequence of hormonal changes associated with the menstrual cycle, pregnancy, postpartum period, or hormonal imbalance due to any disease. The pigmentation is called chloasma. Specialists do not recommend independent treatment in such a case, as it is important to accurately diagnose and treat the underlying disease;

Mechanical damage to the skin. The formation of pigment spots as a result of attempts to treat acne improperly, in chronic and severe furunculosis, due to the effects of chemical and thermal factors (burns), as well as violation of the protocols of some cosmetic procedures (chemical peels, laser resurfacing, etc.). The intensity varies considerably and depends directly on many components – the characteristics of the skin of the individual patient, the degree and depth of injury;
Aggressive exposure to ultraviolet light. Pigment spots of this type are provoked by aggressive exposure to sunlight or other sources of ultraviolet light. They often appear on the face, since the skin of this area of the body is the thinnest and most vulnerable;

skin aging. At a certain age (after 40-50 years and older), some people get characteristic age spots that are located on the face, neck and hands. This is the result of active melanin synthesis and its uneven distribution in the skin layers, as well as changes in the hormonal balance and natural aging of the body and the skin in particular. In addition, pigmentation at this age may be a consequence of the manifestation of various chronic diseases. Such a condition is not usually dangerous for a person, but it does require more careful monitoring of the state of health.

Other causes of pigmentation include gastrointestinal diseases and kidney pathologies, deficiency of vital vitamins or minerals, the use of certain medications (especially uncontrolled or prolonged), and allergic manifestations due to the use of poor-quality or unsuitable cosmetics and care products.

Pigmentation treatment

The basic principle of therapy is to determine the cause and treatment adapted to this factor. A consultation with the physicians should be undertaken:

• therapist;
• gynecologist;
• gastroenterologist;
• endocrinologist.

Special cosmetic procedures. Performed only in specialized institutions and only by experienced professionals, otherwise serious complications are possible. When choosing a method of treatment, both the severity of pigmentation, and the area of location, and the nature of the spot, its shape and size, as well as indications and contraindications for a particular method in each patient are taken into account.

The main ways to combat skin pigmentation include:

Peeling (ultrasound and chemical method). The chemical method uses various acids (azelaic, glycolic, kojic, etc.) The result is the regeneration of the epidermis. The application of the ultrasound method requires special equipment which is used to introduce various preparations into the skin. The result is regeneration and whitening of the skin.
A modern method is laser peeling. Performed with a special equipment, the laser beam removes a layer of skin, triggers the mechanisms of its renewal and rejuvenation. The method belongs to the most progressive and gentle, after which the list of negative complications is limited, although the method is quite traumatic and accompanied by painful sensations. Usually after the procedure is recommended to use special healing agents, and advice is given on skin care throughout the rehabilitation period and after it. Treatment should be planned in winter, as in spring and summer the skin is exposed to the aggressive effects of solar radiation and this aggravates the rehabilitation period. Laser, when used correctly, provides excellent results – rejuvenation of the skin, increasing its elasticity, the acquisition of a beautiful and even color.
The method of phototherapy. Light impulses are used, which affect only problematic areas. The result is the destruction of cells containing an excessive amount of melanin.