Forms of collagen and their use in cosmetology

Dobrinka Mavrova, Kharkov Medical Academy of Postgraduate Education, “Dobrinka Mavrova Clinic” (Ukraine)

Gennady Mavrov, Kharkov Medical Academy of Postgraduate Education, Dobrinka Mavrova Clinic (Ukraine)

Collagen: typology and functions

Collagen is the main protein in the human body, accounting for about 30% of the total protein mass. Up to 40% of collagen is concentrated in the skin, where it performs a structural function, participating in the organization of the dermal matrix, provides intercellular interaction, and plays a critical role in reparative processes. The quality of the collagen framework determines the strength and elasticity of the skin. Today, about 20 types of collagen are known, differing from each other in their structure.

The main component of the skin is type I collagen. Its amino acid composition has a number of features. Collagen contains oxidized forms of amino acids: hydroxyproline and hydroxylysine. Moreover, the primary structure of this protein is characterized by multiple repetitions of three amino acids, most often glycine, proline, hydroxyproline (collagen motif). Due to this, under physiological conditions, such a chain twists into a left-handed helix, each turn of which contains three amino acids (secondary structure of the protein). Three polypeptide chains combine into a single right-handed superhelix, forming the characteristic tertiary structure of collagen, stabilized by hydrogen and covalent disulfide bonds. All these processes occur inside fibroblast cells on the endoplasmic reticulum. Glycosylation also occurs here: monosaccharides (glucose or galactose) are added to the amino acid residues of hydroxylysine. Thus, procollagen is synthesized, which is secreted into the extracellular matrix, where further events unfold. With the participation of peptidase enzymes, the terminal sections of the molecule are split off, and tropocollagen is formed. Its molecule has a three-helical structure, the length of which is 300 nm, and the molecular weight is 300 kDa. In connective tissue, tropocollagen molecules self-assemble into supramolecular structures - fibrils, which can then combine into fibers that are strengthened due to intra- and intermolecular cross-links. Proteoglycan molecules are adsorbed on the surface of collagen fibrils in tissues. It is these structures that ensure the ordering of the extracellular matrix and regulate the functional activity of cells under normal conditions and pathologies (for example, during injuries, including as a result of invasive aesthetic procedures).

The formation of the spatial structure of collagen and the formation of fibrils is a key point in the organization of tissue structure, normal or pathological, such as scar tissue. In the scar area there are always collagen fibers modified in architecture, hastily formed from “immature” collagen during the wound healing process. At the same time, the ratio of different types of collagen and the spatial orientation of protein structures change. In keloid scars, for example, type III collagen predominates, characteristic of the period of embryogenesis.

If we consider healthy skin, then a complete dermal collagen framework provides its turgor, density, firmness, and elasticity. As the body ages, biological macromolecules “wear out.” In relation to collagen, “aging” occurs due to non-enzymatic glycation and the formation of additional cross-links. At the same time, the structure of the fibers is excessively strengthened, their hydrophilicity decreases, and their rigidity and fragility increase. Such altered structures are resistant to the effects of tissue enzymes - collagenases (matrix metalloproteinases), so their renewal is significantly slowed down. The external reflection of these processes is sluggish, flabby, inelastic skin with folds and wrinkles. Aging of collagen (and, accordingly, skin) is accelerated by stress, illness and injury, and aggressive environmental factors. The effect of UV irradiation is quite contradictory: it simultaneously stimulates both the degradation of protein fibers and the formation of intermolecular cross-links.

Injectable forms of collagen and their use in medicine

The variety of biological functions of collagen, the significant role of the collagen matrix in the processes of skin aging and wound healing, on the one hand, and the known raw material sources and the possibility of obtaining protein of a sufficiently high degree of purity, on the other, have created the prerequisites for the production and study of various medical materials based on collagen. Moreover, exogenous collagen is not only a form-forming agent and a transport medium for drugs, but also itself has biological activity, stimulating reparative processes.

As for allergenicity (a question that is often raised in connection with the use of collagen-containing preparations), in general it can be assessed as low, although the risk of allergic reactions cannot be completely excluded. There is evidence that special alkaline-salt treatment of raw materials leads to a decrease in the antigenic properties of collagen. However, in this case, the formation of hypersensitivity is possible.

Injectable forms of collagen are widely used in aesthetic medicine for contouring of various skin defects: wrinkles, folds, normotrophic and atrophic scars, as well as for modeling lips, cheekbones, and chin. Collagen injections can be considered as an etiopathogenetic therapy for age-related changes. The migration of fibroblasts to the area of insertion of collagen implants, stimulation of their synthetic activity, which is manifested by an increase in the amount of newly synthesized collagen and glycosaminoglycans, has been proven.

Since 1981, about a million patients around the world have resorted to intradermal collagen injections, with collagen-containing preparations gaining the greatest popularity in the United States. Canada, UK. According to the ASPS (American Society of Plastic Surgeons), collagen injections were ranked fifth among all aesthetic procedures in 2003.

Collagen-containing preparations have found wide application in various fields of medicine and dermatology. They are used for:

• contour plastic surgery of wrinkles of various depths and localization;
• contour plastic surgery of various anatomical areas;
• correction of stretch marks, scars of various origins;
• plastic reconstructive surgery;
• dentistry;
• orthopedics and traumatology.

Correction of cosmetic imperfections

Despite the rapid development of cosmetology, the problem of age-related skin changes still remains relevant. With age, the skin undergoes the aging process, clinically this is manifested by a decrease in its turgor, elasticity, and the appearance of wrinkles and folds.

The best solution to the problem of age-related changes is the use of collagen-containing material, which will act in three main directions:

• firstly, with collagen injection, folds and wrinkles are mechanically filled with the injected gel, and as a result the skin surface is leveled;
• secondly, collagen injection stimulates the body’s recovery processes in such a way that at the site of intervention, its own collagen fibers begin to be synthesized, which fill the wrinkle or fold;
• thirdly, a collagen-containing drug administered intradermally acts as a kind of template for the formation of new tissue, due to which the growth of its own fibers does not occur randomly and chaotically, but in a strictly directed manner, while eliminating the formation of scars and cords.

As the wrinkle or fold is filled with its own tissue, the injected drug is gradually absorbed, skin turgor and tone are restored, its structure improves, which helps reduce the depth and severity of wrinkles.

The technique of pinpoint microinjections is used to reduce signs of aging, smooth out the relief, restore hydrobalance, and normalize skin elasticity. It is also successfully used in patients with sagging skin on the inner surface of the shoulders and thighs, to restore turgor and elasticity of the skin of this anatomical area, as well as to correct excess skin of the face and skin over the knee joint.

Linear and fan correction techniques are used for involutional-depressive changes in the face.

Scar treatment

Skin scars of various origins are a common cosmetic defect. They often occur as a result of burns, inflammatory processes, various diseases and surgical interventions.

Essentially, a scar is a product of pathological regeneration that occurs at the site of the inflammatory process after any damage to the skin.

When scars of various origins form, random cell growth occurs, leading to the formation of an aesthetic defect. Clinically, this is manifested by decreased elasticity, thinning of the skin, fiber atrophy, pigmentation and depigmentation.

Treatment of scars belongs to the highest level of complexity in dermatocosmetology. Currently, there are several approaches to the treatment of atrophic scars: laser resurfacing, dermabrasion, medium and deep peels, and skin graft transplantation can be used. But with extensive lesions, these methods are not always acceptable. We believe that the best solution to the problem of scars is the introduction of microimplants that fill the defect.

Injections of collagen preparations in the treatment of atrophic cosmetic scars have a number of undeniable advantages. Intradermal administration of a collagen-containing drug leads to mechanical filling of the correction zone, increased migration of fibroblasts, launching the mechanism of synthesis of its own young collagen and restoration of the structure and function of connective tissue. The drug has high biocompatibility with human tissues, is non-toxic, does not migrate, and does not cause the formation of a fibrous capsule.

Treatment of stretch marks

According to statistics, 70% of teenage girls and 40% of boys have clinical manifestations of striae. This problem also often occurs during pregnancy. The mechanism of formation of striae is similar to the mechanism of formation of atrophic scars. Trigger factors in this case may include intense sports, a sharp increase in body weight, and endocrine disorders.

Treatment of stretch marks has its own characteristics at different stages. Patients at risk (with a genetic predisposition, adolescents, people with endocrinopathies, prone to sudden weight fluctuations) need preventive care for those areas where stretch marks usually appear. Since the skin there is thinner and less durable, to strengthen it, you can use products that provide long-term hydration, improve trophism and elasticity, and stimulate collagen formation.

Treatment of existing stretch marks is carried out depending on the stage of development of the pathological process. Treatment can begin when the stretch marks are just forming and have a reddish or purple color. The actions here will be similar to preventive ones, but using a 15% gel. If the problem has gone further and you have to deal with already formed stretch marks, the same drugs are used, but their ratio changes. The therapy procedure covers both the stretch marks themselves and the area of their localization. In this case, the depth of drug administration should be 4 mm. The places of “injections” are the striae themselves and the areas around them. If the patient has stretch marks whose width exceeds 5 mm, regardless of how long they have existed, injections are carried out only along their contour for three sessions. Subsequent management tactics for such patients do not differ from those described previously. Of the complementary techniques, it is preferable to use superficial nappage and papular techniques. On average, the duration of the course is 10–12 procedures. Depending on the results, the course can be repeated 2 times a year.

First published: Les Nouvelles Esthetiques Ukraine, No. 3 (85), 2014