Platelet Rich Plasma (PRP) is currently one of the hottest topics in orthopaedics. This is a biologic concentrate of the patient’s own blood, made using a special machine, and there is now considerable interest amongst many medical device companies in perfecting the technology. But why? The promise of PRP is based upon a a better understanding of what platelets actually do. That is a story best understood when you examine just what is in our bloodstream.
Blood is red because it carries hemoglobin, the oxygen carrying molecule. In addition to red blood cells, blood contains white blood cells, in a far lower amount, that both fight infections and control immunity. There are very few stem cells in our peripheral blood- these are largely contained in the bone marrow, and even there, only in small numbers (1/10,000). In addition, the bone marrow manufacture, in very large numbers, tiny fragments of cells, the platelets. A normal platelet count is several hundred thousand per cubic mm., so there really are a lots of these floating around.
When I was in medical school, we learned that platelets are necessary for proper blood coagulation. Drugs like aspirin thin blood by affecting the way platelets “stick”; and that was pretty much all we learned about platelets. It turns out that platelets do more than that…a lot more. They are chock full of proteins that are critical to processes of inflammation and healing. Only recently has it been possible (see my section on Proteomics) to analyze just what is inside the platelet, because each protein is present in only tiny amounts. and there may be as many as 1000 different proteins!
The PRP proteins include TGFBeta, and Interleukin-2, powerful modulators of cell growth and inflammation. For this reason, a concentrate of platelets is bioactive. It is our job to apply these natural materials to situations where the body can help itself.