Platelet rich plasma therapy: inflammatory molecules involved in tissue healing.

Inflammation represents a fundamental aspect of the healing process. Besides their primary role in hemostasis, platelets play an active role in the immunological and inflammatory aspect of tissue healing. Indeed , they can be directly involved in the inflammatory response by the production and release of several inflammatory mediators, including a variety of cytokines, such as TGF-beta, IL-1 beta, CD40L, and chemokines, such as CXCL7, CXCL4, CXCL4L1, CCl5, CXCL1, CXCL8, CXCL5, CXCL12, CCL2, CCL3. Platelet are not only a source of several chemokine involved in the inflammatory response and tissue healing, but they also express chemokine receptors, in particular CCR1 CCR3 CCR4 and CXCR4, thus being able to being able to regulate the inflammatory response associated to the healing process. However, this local inflammation must be taken under control, and platelets can prevent the excess of leukocytes recruitment by anti-inflammatory cytokines, such as TGF-beta. For this biological properties of platelets, platelet rich plasma therapy (PRP) is considered an innovative and promising approach that has been extended to many field of medicine, ranging from non-union defects, bone fractures, spinal fusion, bone implant and osteointegration, joint arthroplasty, to the treatment of several traumatic or degenerative pathologies of tendons, cartilage and ligaments.