Research progress of PRP in scrofula protection

Clinically,according to the histological and morphological characteristics of scars, they can be divided into superficial, hypertrophic, atrophic and keloid scars. Superficial scars often involve the epidermis or the superficial dermis, and generally do not require special treatment clinically; while hypertrophic and atrophic scars and keloids not only affect the appearance, but in severe cases, they can cause functional impairment and affect the lives of patients.

Platelet rich plasma (PRP) is the plasma containing high concentration of platelets extracted by centrifuging autologous blood. Since PRP was used for tissue repair and regeneration in the 1970s, its research has mainly focused on the application in the musculoskeletal and maxillofacial fields. In recent years, it has been widely used in hair loss, acne, wrinkles, stretch marks, chronic ulcers, scars, as well as enhancing laser resurfacing and postoperative wound healing due to its self-source, no risk of disease transmission, immune rejection, and convenient material collection. and other plastic surgery fields.

  

Prevention

The key to preventing scar formation is to create good healing conditions for the wound surface, such as secondary trauma caused by infection, which can promote early primary wound healing. Wound healing can be divided into three stages: inflammation, proliferation, and remodeling. Platelets play a key role in the three stages of wound healing. The faster the wound healing speed, the lower the probability of scar formation. High concentrations of platelets act on the Injured sites can accelerate and optimize wound healing.

Fang and others divided 30 patients who received skin grafting surgery for various reasons into a Vaseline gauze dressing control group and a PRP gel treatment group. The results showed that the application of PRP gel can promote wound healing, relieve pain, and reduce non-contact low frequency Ultrasound can accelerate scar formation at the donor site of split-thickness skin grafts (STSG), and PRP can promote epithelialization and angiogenesis at the grafted site, effectively reducing scar formation. Its mechanism of action is related to several important growth factors released by platelets, especially transforming growth factor-β (transforming growth factor-β, TGF-β). TGF-β is an important regulator of wound healing, which can trigger inflammatory responses, regulate Epidermal remodeling, regulating the production of extracellular matrix, promoting the regeneration of connective tissue, is most closely related to scar growth. Collagen is the main extracellular matrix component that maintains the tensile strength and elasticity of the skin. In the early stage of granulation tissue, the collagen bundles are thin, randomly arranged, and contain many fibroblasts, while in the late stage, the collagen bundles are dense, closely packed, and arranged in an orderly manner. In PRP-treated skin wounds, dense, parallel, wavy bundles of collagen formed at an early stage, demonstrating that PRP accelerates the maturation of granulation tissue and promotes re-epithelialization.

As PRP contains high concentrations of platelets, leukocytes, and fibrin, high-concentration platelets contain both α and dense granules. After being activated by thrombin, α granules store and release a large amount of growth factors, such as platelet derived growth factor (platelet derived growth factor). , PDGF), TGF-β, vascular endothelial growth factor, epidermal growth factor, etc. These growth factors and other proteins, such as adhesion molecules and chemokines, can regulate cell differentiation, migration, proliferation and angiogenesis, and have the ability to promote tissue Function repair, while high concentration of white blood cells can play a good anti-infection effect, a large amount of fibrin contained in PRP provides a good scaffold for cell repair, not only promotes wound contraction, blood coagulation, but also stimulates tissue regeneration, Promotes wound closure. Therefore, PRP plays a huge role in the prevention of scar formation.

Treatment

01

Keloid scar

Keloid is a benign fibroproliferative disease of the skin, a unique pathological phenomenon arising from skin damage, often occurring after minor trauma or any form of trauma in genetically susceptible individuals, and clinically manifested as being raised above the surrounding normal skin , "crab-like" mass that infiltrates and grows into surrounding tissues, and is prone to relapse after treatment. Its histological features are hyperproliferation of fibroblasts and excessive deposition and disordered arrangement of extracellular matrix, especially collagen.

PRP plays a regulatory role in the anabolic and catabolic processes of wound healing after keloid excision, and thus plays an important balancing role in the tissue repair process by helping to restore the natural balance in the tissue repair process. Jones and others evaluated 49 patients who underwent surgical resection of ear keloids. After surgical resection, PRP was applied to the wound site, followed by superficial photon X-ray irradiation. After an average follow-up of 24 months, 94% of keloid patients had no recurrence.

02

Atrophic scar

The damage of atrophic scar often involves the whole layer of skin and subcutaneous fat tissue, which can be formed after surgery, trauma and acne healing. It is hard and flat, has poor local blood supply, closely adheres to deep tissues such as nerves, muscles, tendons, etc., and the thin epidermis is easy to rupture, thus forming chronic ulcers that will not heal for a long time. PRP can actively correct atrophic scars by releasing a variety of growth factors, attracting undifferentiated cells into the newly formed matrix, triggering cell division, and promoting the generation of new capillaries.

After PRP combined with skin microneedling treatment, it can accelerate tissue repair, increase the healing mechanism, and stimulate the skin to produce more collagen. The new collagen helps to improve skin texture, atrophic scars, and reduce long-term erythema and other adverse reactions. Some researchers evaluated and compared the efficacy and safety of microneedle, PRP, and the combined application of the two in the treatment of atrophic scars, and found that the combined treatment of microneedle and PRP is more effective, safer, and shorter in duration of treatment for all types of atrophic scars .

Studies by Makki et al have shown that PRP combined with CO2 laser is safer, more effective, and has fewer adverse reactions in the treatment of post-traumatic scars. Chang et al conducted a Meta-analysis on the efficacy of PRP combined with CO2 laser in the treatment of atrophic scars after acne, and the results showed that the duration of erythema and edema after combined treatment was relatively short, and the satisfaction rate of patients after combined treatment was significantly higher than that of laser alone For treatment, autologous PRP combined with CO2 laser has a significant effect on atrophic acne scars and can accelerate the recovery of laser-damaged skin. The above studies have proved that PRP, as an adjuvant laser therapy, can accelerate the recovery time of the skin after laser damage, and reduce the adverse reactions such as erythema, swelling, pain, and pigmentation after treatment.

03

Hypertrophic scar

Hypertrophic scars are piled up that accumulate in the deeper layers of the dermis, caused by excessive fibroblast synthesis and collagen deposition. Commonly seen in donor sites where medium-thick skin flaps are cut, after healing of deep second-degree burns, inflammation, cutting wounds, foreign bodies, etc. The clinical manifestations are red color, hard texture, and local thickening higher than normal skin. Cytokines play an important role in hypertrophic scars. Recent in vitro studies have shown that certain bone morphogenetic proteins (bone morphogenetic proteins, BMPs) prevent or even reduce the formation of hypertrophic scar tissue by inducing lipotransformation of myofibroblasts within the scar. Since platelets contain BMPs in their granules, PRP may serve as a carrier to deliver BMPs to the scar site. In addition, when PRP is mixed with adipose graft tissue, it releases synergistic adipose growth factors (including BMPs), which help complete myofibroblast transformation and adipogenesis.

Forecast

PRP has shown its unique advantages in the prevention and treatment of scars, but the effect of PRP in the prevention and treatment of scars still needs to be verified by standardized PRP preparation, large samples, long-term follow-up, and multi-center clinical prospective randomized controlled studies. At present, there are few studies on PRP for hypertrophic scars, because hypertrophic scars are different from atrophic scars and have their unique characteristics. Therefore, future research should focus on the prevention and treatment of hypertrophic scars, such as the effects of various growth factors released by PRP on the prevention and treatment of hypertrophic scars, and the clinical effect of PRP combined with prevention and treatment of hypertrophic scars. A new method of prevention.

References: Zhang Min, Bai Yu. Research progress of platelet-rich plasma in the prevention and treatment of scars[J]. Chinese Journal of Aesthetic Plastic Surgery，2022，33（11）：686-688.