Biology of platelet-rich plasma

Platelets are anucleate derivatives of megakaryocytes that can release almost 4000 unique proteins stored in one of three types of granules: dense granules, alpha (A)-granules, or lysosomes. Platelet A-granules release several growth factors (GFs), cytokines, chemokines, and proteolytic enzymes that can promote healing and tissue regeneration by stimulating cell proliferation, differentiation, migration along with matrix remodeling, and angiogenesis. Treatment using autologous preparation of platelet-rich plasma (PRP) containing platelets whose concentration is three- to fivefold above baseline in the blood is widely popular in sports medicine and maxillofacial surgery, and more recently has gained traction in dermatology. PRP preparation is rapid, requiring minimal specialized equipment and training, and is relatively safe, easy, and affordable compared to other tissue regeneration therapies such as tissue engineering, gene therapy, or cell therapy. GFs secreted by platelets in PRP cause dermal matrix remodeling to enhance skin rejuvenation and healing of wounds and scars while keratinocyte and dermal papilla cell growth and proliferation are key features induced by GFs to promote wound healing and hair regeneration. Although achievements from use of PRP in clinical dermatology are invigorating, there is limited understanding about the basic science further complicated by lack of standardization in the clinical setting resulting in variable and inconsistent clinical response.