Platelet-rich plasma (PRP) is blood plasma that has been concentrated and enriched with platelets. Platelets are a specialized type of blood cell involved with healing and also contain large reservoirs of natural growth factors that are essential for cell recruitment and proliferation involved in wound/injury healing.
As a concentrated source of platelets, PRP contains several different growth factors and other cytokines that stimulate healing of bone and soft tissue. Growth factors are compounds instrumental in attracting other cells that aid healing, stimulating new blood vessel formation helpful in the healing process, and promoting cell reproduction necessary for healing.
Some of the different cytokines contained in PRP injections are:
- Mitogenic (growth) factors
- Platelet derived growth factor (PDGF), fibroblast growth factor (FGF), hepatocyte growth factor (HGF), transforming growth factor beta (TGF-?)
- Angiogenic growth factor (which helps promote blood flow and recruitment)
- Vascular endothelial growth factor (VEGF), transforming growth factor beta 1 (TGF-?1)
- Matrix-building proteins
- Fibrinogen, fibronectin, vitronectin
- Anti-inflammatory proteins
- Alpha-2-macroglobulin (A2M), interleukin-1 receptor antagonist protein (IRAP)
Processing the blood into PRP increases the concentration of these cytokines and PRP procedures are commonly used for soft tissue injuries and osteoarthritis.