When is PRP Therapy done
Platelet-Rich-Plasma Therapy, also known as Autologous Conditioned Plasma Therapy is an emerging treatment modality primarily used for Androgenetic alopecia, i.e., hair loss mainly due to hormonal and genetic factors. It is done by collecting patient’s own plasma, separating and concentrating its contents and injecting the platelet-rich plasma intradermally or subdermally into the patient’s scalp (area of hair loss). Plasma is collected via minimally invasive techniques and then centrifuged. The final product is devoid of RBCs, has minimal leucocytes and is rich in platelets. Sometimes exogenous platelet activators are added to the final product. Once injected into the scalp, the platelets get activated and secrete growth factors. Active growth factor secretion occurs within 10 minutes of injection and >95% growth factors are released within 2 hours. Active growth factor synthesis continues for 7 days. These growth factors promote hair growth.
Growth factors contained within the dense granules of platelets act on stem cells in the bulge area of hair follicles and stimulate the development of new follicles, along with neovascularisation. Activated platelets release growth factors such as PDGF, VEGF, TGF, EGF, IGF-1 etc. They promote cell proliferation, differentiation, fibroblast activation, collagen synthesis, stimulation of extracellular matrix and overexpression of endogenous growth factors, that is necessary for new hair growth.
Stages of hair growth are anagen or growing phase, catagen phase or transition phase and telogen or resting phase. Around 10-15% of the hair is in the telogen phase. Whilst the old hair is resting, a new hair begins the growth phase. IGF-1 has been shown to induce and prolong the anagen phase. The dense granules in platelets contain bioactive factors such as serotonin, histamine, calcium, adenosine etc. that increases membrane permeability and modulates inflammation. Activated platelets have also been reported to induce the proliferation of dermal papilla cells by activating Extracellular signal-related kinase pathway and protein kinase B- a chemical that prevents cell death. The growth factors released by activated platelets upregulate the ERK pathway leading to increased transcription of genes involved in cellular proliferation and differentiation.
PRP Therapy also causes angiogenesis and increased vascularization of the hair follicle. In androgenetic alopecia, there is reduced blood flow and oxygen pressure, leading to hair loss. The growth factors in PRP Therapyact on stem cells found in the bulge area of follicles, resulting in neovascularization and folliculogenesis. Increased production of a chemical, beta-catenin, which is believed to increase dermal papilla cell survival, proliferation and angiogenesis were also seen.
Therefore, in summary, the mechanisms by which PRP Therapy promotes hair growth are increasing the duration of the anagen phase, preventing apoptosis (a type of cell death) and improving vascularization. Due to its autologous origin and minimal invasive collection technique, the risk of infection and immune rejection are minimal and therefore compared to PRP Therapy remains one step above compared to other modes of treatment for Androgenetic alopecia.