Sunday, January 10, 2010

Platelet Rich Plasma

In honour of the Olympics this blog will be dedicated to the topic of Platelet Rich Plasma (PRP). Lately PRP has been getting much media attention as a new miracle cure for athletic injuries. So what exactly is PRP, and how does it work?
If you were to take a tube of unclotted blood and spin it in a centrifuge, it would separate into two portions, a liquid portion called plasma, and a solid portion made up of cellular elements. The cellular portion would be divided into three categories. The largest portion would be the Red Blood Cells (RBC), responsible for carrying oxygen to the tissues. The next portion would be the White Blood Cells (WBC), the cells responsible for the body’s immune system. The final type of cells found would be the platelets, the cells responsible for blood clotting.
It is because of this function that platelets have been getting a lot of bad press lately. After all, circulatory disease is the major killer in the industrialized world, all caused by the blood flow to tissue interrupted by the formation of platelet clotting. A lot of treatment such as aspirin and plavix, is based on reducing the clotting activity of platelets, so why would someone want to inject plasma that has an increased concentration of platelets?
Because despite the fact that platelet clumping can lead to death, platelets do more than stop blood flow when they are activated.
After all, without platelets we would all die from bleeding to death. When tissue is damaged, it releases chemicals that activate platelets to clump and form a plug to prevent blood from leaking out. Once activated, platelets will also release chemicals from granules inside of them. These chemicals help the body to start repair the damage to the tissue.
Two of the most important activators are Platelet Derived Growth Factor (PDGF) and Transforming Growth Factor Beta (TGF-β). PDGF attracts WBC, fibroblasts and smooth muscle cells to the injury site. Once there these cells begin tissue repair by the formation of new cells, capillary networks that increase blood flow to the damaged tissue and fibronectin, a cellular super glue that holds all of this together. TGF-β also attracts cells to the damaged tissue and also causes cells to increase production of collagen and fibronectin.
In 1986 researchers l decided to see if platelets could be used to heal tissue. By centrifuging blood at a certain speed, WBC and RBC’s will sink to the bottom, while leaving platelets to float in the plasma at increased levels. The plasma, now rich with platelets is then removed. By adding chemicals to activate the platelets to begin clotting, a gel forms that can be applied to wounded tissue to speed up repair. This has been used successfully in different types of surgery to speed up recovery.
Recently though, doctors in sports medicine have decided trying injecting the PRP straight into the damaged area, usually a soft tissue injury such as Achilles tendonitis. Many famous athletes have received this type of treatment with resounding success.
Recent studies have shown this to be due mostly to a placebo effect. Researchers injected patients with either saline or PRP, and received the same results. Their conclusion was that using PRP for soft tissue injury caused by a sports injury was useless.
However using PRP by activating the platelets to form a gel has been found to help patients recover from surgery or unhealed ulcers.