Throughout times, the autologous blood concentrate has accumulated considerable attention from scientists and clinicians; particularly in the field of cosmetics, orthobiologics, and sports injuries associated with musculoskeletal disorders. Studies have confirmed that the ability of platelet-rich plasma to promote the huge secretion of different growth factors and trigger a cascade of communication pathways is the key to its widespread therapeutic applications.
What are different bioactive factors?
Platelets are active components of our immune systems that are developed in the bone marrow from megakaryocytes and are having a lifespan of about 7 to 10 days. The active platelet components are known as three different types of granules, mainly alpha, delta, and lambda granules; constituting about 10% of the total platelet volume. These granules contain a lot of important membrane-bound proteins including integrins, platelet endothelial cell adhesion molecules (PECAM), immunoglobulin family receptors, etc. These membrane-bound proteins are released into extracellular space, which acts as networking signals for better communication. Other than the same there are almost 300 soluble proteins that trigger communication channels for passage of different repairing as well as healing processes.
On a general note, all the functional properties of PRP are always based upon the cytokine profile secreted by platelets. All the important factors mentioned herewith are essentially stored in alpha granules of thrombocytes with an important role in regulating key processes, such as chemotaxis, regulatory mitogenesis, as well as cellular differentiation. Moreover, these cells also promote local mesenchymal tissue-specific stem cells to migrate towards the site of injury along with vascular endothelial cells. These cells then play an important role in vascularization, tissue regeneration, and healing. Some of the important growth factors released by platelets are:
- Platelet-Derived Growth Factors: Promotes collagen synthesis that contributes elasticity to your skin, is accounted for promoting cellular proliferation, as well as macrophage activation.
- Transforming Growth Factor: They are responsible for enhancing the synthesis of type 1 collagenase, promotes revascularization, etc. This anti-inflammatory cytokine is also responsible for inhibiting toxic cell formation and bone resorption.
- Vascular Endothelial Growth Factor: Promotes formation of new blood vessels, activates migration of endothelial cells and mesenchymal stem cells to the site of injury.
- Epidermal Growth Factors: This is responsible for cellular proliferation, revascularization, secretion of important cellular products of mesenchymal stem cells and endothelial cells.
- Fibroblast Growth Factors: This is important for promoting the proliferation of resident mesenchymal stem cells, as well as the growth of several other cells.
Today, there are almost 40 different commercial kits available in the market that help separate as well as concentrate platelets from blood plasma. In the majority of the systems available, the optimized protocol requires at least two centrifugation steps; however, some systems are available that are optimized for a fivefold concentration of platelets with a short process of single centrifugation.