Рубцовая ткань: образование, типы и особенности

Area of fibrous tissue that replaces normal skin after an injury
scar tissue<! A scar (or scar tissue) is an area of fibrous tissue that replaces normal skin after an injury. Scars result from the biological process of wound repair in the skin, as well as in other organs, and tissues of the body. Thus, scarring is a natural part of the healing process. With the exception of very minor lesions, every wound (e. g., after accident, disease, or surgery) results in some degree of scarring. An exception to this are animals with complete regeneration, which regrow tissue without scar formation. Scar tissue is composed of the same protein (collagen) as the tissue that it replaces, but the fiber composition of the protein is different; instead of a random basketweave formation of the collagen fibers found in normal tissue, in fibrosis the collagen cross links and forms a pronounced alignment in a single direction. This collagen scar tissue alignment is usually of inferior functional quality to the normal collagen randomised alignment. For example, scars in the skin are less resistant to ultraviolet radiation, and sweat glands and hair follicles do not grow back within scar tissues. unlike normal tissue which distributes fiber elasticity. Scars differ in the amounts of collagen overexpressed. Labels have been applied to the differences in overexpression. Two of the most common types are hypertrophic and keloid scarring,

Hypertrophic scars occur when the body overproduces collagen, which causes the scar to be raised above the surrounding skin. Hypertrophic scars take the form of a red raised lump on the skin for lighter pigmented skin and the form of dark brown for darker pigmented skin. They usually occur within 4 to 8 weeks following wound infection or wound closure with excess tension and/or other traumatic skin injuries.

Keloid scars are a more serious form of excessive scarring, because they can grow indefinitely into large, tumorous (although benign) neoplasms. Keloid scars can occur on anyone, but they are most common in dark skinned people. They can be caused by surgery, cuts, accident, acne or, sometimes, body piercings. In some people, keloid scars form spontaneously. Although they can be a cosmetic problem, keloid scars are only inert masses of collagen and therefore completely harmless and not cancerous. However, they can be itchy or painful in some individuals. They tend to be most common on the shoulders and chest. Hypertrophic scars and keloids tend to be more common in wounds closed by secondary intention. chickenpox, other diseases (especially Staphylococcus infection), surgery, certain insect and spider bites, or accidents. It can also be caused by a genetic connective tissue disorder, such as Ehlers–Danlos syndrome.

Stretch marks (technically called striae) are also a form of scarring. These are caused when the skin is stretched rapidly (for instance during pregnancy, significant weight gain, or adolescent growth spurts), or when skin is put under tension during the healing process (usually near joints). This type of scar usually improves in appearance after a few years.

Humans and other placental mammals have an umbilical scar (commonly referred to as a navel) which starts to heal when the umbilical cord is cut after birth. Egg laying animals have an umbilical scar which, depending on the species, may remain visible for life or disappear within a few days after birth.

An injury does not become a scar until the wound has completely healed; this can take many months, or years in the worst pathological cases, such as keloids. To begin to patch the damage, a clot is created; this clot is the beginning process that results in a provisional matrix. In the process, the first layer is a provisional matrix and is not a scar. Over time, the wounded body tissue overexpresses collagen inside the provisional matrix to create a collagen matrix. This collagen overexpression continues and crosslinks the fiber arrangement inside the collagen matrix, making the collagen dense. This densely packed collagen, morphing into an inelastic whitish collagen To mend the damage, fibroblasts slowly form the collagen scar. The fibroblast proliferation is circular

Early and effective treatment of acne scarring can prevent severe acne and the scarring that often follows. In 2004, no prescription drugs for the treatment or prevention of scars were available.

Chemical peels are chemicals which destroy the epidermis in a controlled manner, leading to exfoliation and the alleviation of certain skin conditions, including superficial acne scars. Various chemicals can be used depending upon the depth of the peel, and caution should be used, particularly for dark skinned individuals and those individuals susceptible to keloid formation or with active infections.

Filler injections of collagen can be used to raise atrophic scars to the level of surrounding skin. Risks vary based upon the filler used, and can include further disfigurement and allergic reaction.

Nonablative lasers, such as the 585 nm pulsed dye laser, 1064 nm and 1320 nm Nd:YAG, or the 1540 nm Er:Glass are used as laser therapy for hypertrophic scars and keloids. There is tentative evidence for burn scars that they improve the appearance. Ablative lasers such as the carbon dioxide laser (CO) or Er:YAG offer the best results for atrophic and acne scars. Like dermabrasion, ablative lasers work by removing the epidermis. Healing times for ablative therapy are much longer and the risk profile is greater compared to nonablative therapy; however, nonablative therapy offers only minor improvements in cosmetic appearance of atrophic and acne scars.

Silicone scar treatments are commonly used in preventing scar formation and improving existing scar appearance. A meta study by the Cochrane collaboration found weak evidence that silicone gel sheeting helps prevent scarring. Pressure dressings are commonly used in managing burn and hypertrophic scars, although supporting evidence is lacking. Care providers commonly report improvements, however, and pressure therapy has been effective in treating ear keloids. Gross morphologic features suggested that the combination of verapamil and silicone improves the overall quality of hypertrophic scars by reducing scar height and redness. This was verified with quantifiable histomorphometric parameters; however, oral verapamil is not a good choice because of its effect of lowering blood pressure. Intralesional injection of verapamil is also suboptimal because of the required frequency for injections. Topical silicone gel combined with verapamil does not lead to systemic hypotension, is convenient to apply, and shows enhanced results. Topical steroids are ineffective. However, clobetasol propionate can be used as an alternative treatment for keloid scars. Topical steroid applied immediately after fractionated laser treatment is however very effective (and more efficacious than laser treatment alone) and has shown benefit in numerous clinical studies.

Scar revision is a process of cutting the scar tissue out. After the excision, the new wound is usually closed up to heal by primary intention, instead of secondary intention. Deeper cuts need a multilayered closure to heal optimally, otherwise depressed or dented scars can result. Surgical excision of hypertrophic or keloid scars is often associated to other methods, such as pressotherapy or silicone gel sheeting. Lone excision of keloid scars, however, shows a recurrence rate close to 45%. A clinical study is currently ongoing to assess the benefits of a treatment combining surgery and laser assisted healing in hypertrophic or keloid scars. Subcision is a process used to treat deep rolling scars left behind by acne or other skin diseases. It is also used to lessen the appearance of severe glabella lines, though its effectiveness in this application is debatable. Essentially the process involves separating the skin tissue in the affected area from the deeper scar tissue. This allows the blood to pool under the affected area, eventually causing the deep rolling scar to level off with the rest of the skin area. Once the skin has leveled, treatments such as laser resurfacing, microdermabrasion or chemical peels can be used to smooth out the scarred tissue.

Research shows the use of vitamin E and onion extract (sold as Mederma) as treatments for scars is ineffective.

The permanence of scarring has led to its intentional use as a form of body art within some cultures and subcultures. These forms of ritual and non ritual scarring practices can be found in many groups and cultures around the world.

First attested in English in the late 14th century, the word scar derives from a conflation of Old French escharre, from Late Latin eschara, which is the latinisation of the Greek ἐσχάρα (eskhara), meaning "hearth, fireplace", but in medicine "scab, eschar on a wound caused by burning or otherwise", and Middle English skar ("cut, crack, incision"), which is from Old Norse skarð ("notch, gap"). ribosomal s6 kinase (RSK), and osteopontin were investigated. In 2011, the scientific literature highlighted stress shielding a fresh wound through the wound healing process, brings significant scar improvement and smaller scars.

By 2016, skin had been regenerated in vivo, and in vitro and scar free healing had been operationalized and induced by four main techniques: regeneration by instrument; regeneration by materials; regeneration by drugs; and regeneration by in vitro 3 D printing. In 2018, a silk derived sericin hydrogel dressing was undergoing research, the material was shown to prevent scar formation. By 2021, more people were paying attention to the possibility of scar revision alongside new technologies.