Platelet-Rich Plasma: Evidence to Support Its Use

SUMMARY:

Platelet rich plasma (PRP) is an autologous concentration of human platelets in a small volume of plasma. Therefore, the term PRP is preferred to autologous platelet gel, plasma-rich growth factors (PRGFs), or a mere autologous platelet concentrate. Because it is a concentration of platelets, it is also a concentration of the 7 fundamental protein growth factors proved to be actively secreted by platelets to initiate all wound healing. These growth factors include the 3 isomeres of platelet-derived growth factor (PDGFaa, PDGF/3/3, and PDGFaB), 2 of the numerous transforming growth factors-0 (TGFal and TGF(32), vascular endo¬thelial growth factor, and epithelial growth factor. All of these growth factors have been documented to exist in platelets.’ ,2 Because these concentrated plate¬lets are suspended in a small volume of plasma, PRP is more that just a platelet concentrate; it also contains the 3 proteins in blood known to act as cell adhesion molecules for osteoconduction and as a matrix for bone, connective tissue, and epithelial migration. These cell adhesion molecules are fibrin itself, fi¬bronectin, and vitronectin.

PRP development via centrifugation has been greatly simplified so that it can be used in the office setting as well as the operating room. However, the centrifugation process must be sterile and precisely suited to platelet separation from red blood cells and  their-sequestration in high concentrations without lysing the platelets or damaging them so that they no longer can actively secrete their growth factors. Therefore, not all currently marketed PRP devices are equal; some do not concentrate viably active platelets in sufficient numbers to produce a healing enhancement. This has led to and explains most of the criticisms regarding the efficacy of PRP. In addition, there have been some research efforts to study PRP in animal models that have a blood volume that is too small to produce PRP; therefore, these studies have used donor blood. This of course is homologous, not autologous, and therefore is not true PRP. The use of donor animal blood platelets imparts an overt im¬mune reaction and leads to false-negative results that may falsely be ascribed to PRP.

Note: The full text article below is posted with the consent of Dr. Robert E. Marx.