Androgenic alopecia (AGA) is one of the most common types of hair loss, a progressive hair loss disorder that starts at puberty or late adolescence with microscopic hair follicles. The prevalence of AGA in China is about 21.3% in males and 6.0% in females. Although scholars have previously proposed guidelines for the treatment of androgenetic alopecia in China, they mainly focus on the diagnosis and medical drug treatment of AGA, and other treatment options are relatively lacking. In contrast, in recent years, with the emphasis on the treatment of AGA, some new treatment methods have emerged.
Aetiology and pathogenesis
AGA is a polygenic recessive disease with a genetic predisposition. Domestic epidemiological surveys show that 53.3%-63.9% of AGA patients have a family history of inheritance, and the paternal line is significantly higher than the maternal line. Current whole-genome sequencing and localization studies have identified several susceptibility genes, but their pathogenesis has not been clarified. Current studies suggest that androgens are a determining factor in the development of AGA; other factors including perifollicular inflammation, increased life stress, stress and anxiety, and poor lifestyle and dietary habits can all exacerbate the symptoms of AGA. Androgens in men mainly come from testosterone secreted by the testes; androgens in women mainly come from the synthesis of the adrenal cortex and a small amount of secretion from the ovaries. Androgens are mainly androstenediol, which can be metabolized into testosterone and dihydrotestosterone.
Clinical manifestations and treatment recommendations
AGA is a form of non-scarring alopecia, which usually develops in adolescence and presents with progressive thinning of hair diameter, reduction of hair density and hair loss until baldness of varying degrees, usually accompanied by increased scalp oil production.
PRP application
Once PRP is activated, a large number of growth factors, including platelet-derived growth factor, transforming growth factor-beta, insulin-like growth factor, epidermal growth factor and vascular endothelial growth factor, will be released from the alpha particles in platelets, which have the effect of improving the microenvironment of hair follicles and promoting hair follicle growth. The specific mechanism of action is not fully understood. The method is to inject PRP locally into the dermis of the scalp in the area of hair loss, once/month, with certain efficacy seen in 3~6 consecutive injections. Although various clinical studies at home and abroad have initially confirmed the effect of PRP on AGA, it can be used as a new means of AGA treatment at this stage.
PRP was first used in surgical patients in 1977 with good efficacy, and in 2011, the International Society of Cellular Medicine launched the Guidelines for the Application of Platelet Rich Plasma. 2018, the first expert consensus interview on the application of PRP in clinical specialities in China, PRP has been promoted in several countries and regions and is widely used in many disciplines, such as maxillofacial surgery, orthopaedics, plastic surgery, ophthalmology, and etc. In 2006, Uebel et al. In 2006, Uebel et al. first attempted to pretreat the follicular units to be transplanted with PRP and observed that compared to scalp control areas. Therefore, it was suggested that growth factors released from platelets may act on the stem cells of the hair follicle bulge to stimulate stem cell differentiation and promote the formation of neovascularization.
In 2011, Takikawa et al. applied saline, PRP, and heparin-fisetin particle-bound PRP (PRP&D/P MPs) to AGA patients subcutaneously in a controlled setting. It was found that the cross-sectional area of hairs in the PRP and PRP&D/P MPs groups was significantly increased, so it was concluded that PRP rich in platelet-derived growth factors regulates cell migration, attachment, proliferation and differentiation, promotes the accumulation of extracellular matrix, and many growth factors positively promote hair growth.
The advent of platelet-rich plasma (PRP) for hair loss has more than given patients a new treatment option that is widely recognized for both its efficacy and safety. However, many people are still relatively new to PRP, so we will now look at the components and effects of PRP, the development of PRP, the advantages of PRP, the contraindications of PRP, and many other aspects.
Composition and role of PRP
Platelet-rich plasma (PRP) is a platelet concentrate extracted from patient blood by centrifugation, containing high concentrations of platelets, white blood cells and fibrin. The platelets injected into the tissue can secrete a variety of growth factors upon activation, the most important of which are the following.
(1) Epidermal growth factor (EGF) regulates cell growth, regeneration and differentiation, and stimulates the regeneration of collagen fibres and keratinocytes.
(2) Transforming growth factor group (TGFG) stimulates the growth of new blood vessels and increases blood circulation.
(3) Vascular endothelial growth factor (VEGF) regenerates blood vessels, regenerates old blood vessels, stimulates endothelial cell mitosis and cell migration, dilates blood vessels, and increases microvascular permeability.
(4) Collagen fibroblast growth factor (FGF) stimulates the growth of neovascularization, granulocytes, epidermal cells, and intrinsic repair of damaged tissues.
(5) Platelet-derived growth factor (PDGF) attracts collagen fibroblasts, promotes collagen production, PDGF promotes macrophage activation and angiogenesis, promotes fibroblast proliferative activity and chemotaxis, increases collagen synthesis, and promotes osteoblast proliferation.
(6) Epidermal keratinocyte growth factor (KGF) promotes keratinocytes’ movement, differentiation and regeneration to create optimal conditions for the repair and regeneration of new skin.
These growth factors play a role in cell movement, differentiation, division, tissue regeneration, angiogenesis, vasodilation, and increased microvascular permeability, among many other things. The platelets and leukocytes in PRP prevent infection, reduce inflammation, and relieve pain. Fibrin builds the three-dimensional structure needed for tissue repair locally, shrinks wounds, and promotes wound healing.
Development of PRP
PRP was first used in surgical patients in 1977, with good efficacy. 2011, the International Society of Cellular Medicine launched the “Guidelines for the Application of Platelet Rich Plasma”. 2018, the first domestic expert consensus interview on the application of PRP in clinical specialities. PRP has been used in many countries and regions and is widely used in many disciplines.
Advantages of PRP injection therapy
First of all, PRP is autogenous, without risk of disease transmission or immune rejection, and is safe and effective. PRP has been used in many countries and is widely used in many disciplines.
Contraindications to PRP treatment
Absolute contraindications include platelet dysfunction syndrome, thrombocytopenia, hemodynamic instability, sepsis, hypofibrinogenemia, etc.
Relative contraindications include prolonged use of anti-inflammatory drugs and systemic corticosteroids, recent fever or weakness, bone tumours, leukaemia, history of Enterococcus, Pseudomonas, Klebsiella, and localized rash at the injection site.
PRP has many biological and chemical functions such as bio gel, coagulation, blood flow stabilization, wound healing, etc. In addition, it can promote the accumulation of growth factors, increase hair regrowth, and facilitate treatment.
PRP treatment requires strict adherence to aseptic procedures in blood collection, preparation, and injection, and the transfusion staff, clinicians, and nurses need to divide their duties and responsibilities. This is not much different in all major hospitals. But why do some hospitals do well, and some are not? The point is that there is a huge difference in the perception of the disease between patients and medical workers, and here the importance of the returning staff comes into play. The callback staff must deal with the communication of various situations before, during and after treatment, inform the patients in advance of what will happen, and explain the treatment methods. This will convince the patient not to panic and be satisfied both physically and psychologically.
