Growth factors derived from platelets affect mitogenic activity of osteoblasts and other undifferentiated cells. At the wound site, the growth factors act on undifferentiated cells with respect to cell recruitment (chemoattraction) and cell division (mitosis). Concentration of platelets well above baseline levels not only increases the attraction of undifferentiated cells to the wound site but also proliferation of those cells. The enhanced cellular proliferation resulting from high platelet concentrations can even allow for a reduction in autograft requirements as well as accelerate bone and soft tissue healing.
- Blood contains bioactive proteins that initiate and control the healing process.
- A small amount of the patient’s blood can be drawn to concentrate these proteins.
- Placing these proteins on the wound site help accelerate the healing process.
- The protein load stimulates cell proliferation in a dose dependant manner.
Normal Platelet
Platelet Rich Plasma, PRP is blood plasma with highly concentrated platelets. Platelets are a specialized type of blood cell involved in injury healing. Platelets also contain large reservoirs of natural growth factors. While a normal concentration of platelets circulating in your blood is 200,000 per micro liter, the platelet count in Platelet Rich Plasma can exceed 2 million platelets per micro liter. To be considered PRP, the platelet count must be 4x or greater above baseline.
Concentrated Platelet
When concentrating platelets, 7 fundamental protein growth factors (also called cytokines) are concentrated.
Platelet-derived growth factors – PDGFaa, PDGFab, PDGFbb
Transforming growth factors – TGFb1, TGFb2
Vascular endothelial growth factors – VEGF
Epithelial growth factors – EGF
This concentrate also contains 3 proteins in the blood to act as cell adhesion molecules: fibrin, fibronectin, and vitronectin. Clinical data has shown that the concentration of growth factors may help optimized conditions for bone healing.
How is Platelet Rich Plasma made?
Platelet Rich Plasma is collected by drawing 20 – 60 cc of blood (500 cc is taken in blood bank donations), the blood is then put into a centrifuge and spun down separating the red blood cells, plasma and concentrating the platelets. Since Platelet Rich Plasma is Autologous (from the self) there is no chance of rejection or adverse effects.
Increasing Bioactivity
BIOLOGY
The response of living tissue to injury forms the foundation of all surgical practice:
• All surgery results in tissue and cellular damage
• The body’s natural response to this injury is a series of regeneration and
remodeling steps collectively referred to as the “Healing Cascade”
• The steps are initiated and controlled by bioactive proteins found in platelets,
plasma and white blood cells
• Cellular regeneration, remodeling, and proliferation requires a combination of:
➤ Scaffold (structure or matrix)
➤ Undifferentiated Cells
➤ Signal Proteins
• Increasing the concentration of bioactive proteins acts as a catalyst for accelerating
the wound healing process and forms the foundation of tissue engineering
Platelet Concentrates Accelerate Growth Factors
The method used for concentrating platelets has a direct impact on the bioactive proteins
available to accelerate the wound healing process:
• In order to deliver the protein load necessary to achieve a bioactive matrix, the platelets and
corresponding growth factors must be concentrated in such a way as to leave them viable
and functionally similar to the ones found in the circulatory system
• The method used to prepare platelet concentrate dramatically affects its effectiveness
• Current research indicates that acceleration of the wound healing process requires viable
platelet concentrations of 4x to 5x above baseline 5, 6
• Enhanced cellular proliferation resulting from high platelet concentrations can even allow
for a reduction in autograft requirements as well as accelerate bone and soft tissue healing 4, 5, 6
• An exponential increase in undifferentiated cell proliferation occurs as platelet
concentrations increase from 2.5x to 5x to 10x above baseline levels 1, 2