We are now offering PRP treatment to our patients. We will inject the recipient area prior to making incisions for the grafts. The recipient area will produce its own thrombin and activate the platelets, thus stimulating them to release their concentrated growth factors. We are also offering PRP gel for the treatment of our donor area extraction sites. We will assess whether it improves healing and whether it improves the overall cosmesis of the donor area. We may find that it helps to reduce the occurrence of white spotting in some of our patients.
Finally, we are offering PRP treatment to our patient's native hair before it falls out. Of course, we cannot predict what the advantages will be for our patients, but we are hopeful that it will improve the coverage for our patients and prolong the life of their native hair. We anticipate that the growth factors will improve the diameter of growing hairs and thus improve the coverage. Of course, it could also improve hair color, the total number of hairs in the growing phase, and the duration of the growing phase (anagen) for our patients. We will begin to study the benefits of PRP in patients who choose to treat their native hair with the PRP.
Patients, who refuse to take medications such as Propecia and Rogaine (Regain), may find that PRP serves as an adequate or better substitute to these medications alone. We will also be able to offer PRP to our female patients who thus far have had very little in the way of pharmacologic treatment for their hair loss.
In short, PRP offers many new treatment options for patients who are undergoing hair transplant surgery and for patients who wish to add a potentially significant additional treatment option to their hair loss.
Platelets were first described in the 1800s by the German anatomist Max Schultze. They are also called thrombocytes. They are formed by fragmentation of megakaryocytes in the bone marrow. They function in helping the body form blood clots or hemostasis. They also serve as a natural source of growth factors. Their life span is 8 to 12 days and the circulating life span is 7 to 10 days.
There are usually 150 to 400 X 109 platelets per liter. Around 1 x 10 to the 11th power platelets are produced each day. Each megakaryocyte produces between 5000 and 10,000 platelets.
Platelets contain dense granules containing ADP or ATP, Calcium, and serotonin and a-granules that contain growth factors, fibrinogen, fibronectin, B-thromboglobulin, vWF, and coagulation factors V and XIII. When platelets are activated they release the contents of these granules.
Platelets are activated by contact with collagen or by thrombin. They may also be activated by contact with the glass.
Thrombin is derived from Prothrombin. The gene for prothrombin is located on chromosome 11. Factor Xa binds with Prothrombin to enzymatically form thrombin. The activity of Factor Xa is enhanced when Factor Va binds with Factor Xa, thus forming a prothrombinase complex. When Prothrombin acts with the prothrombinase complex, thrombin is formed by enzymatic cleavage of two sites on prothrombin.
Platelet-rich plasma is a component of whole blood. There are several different cell types in the blood. One is the red blood cells, which carries oxygen to the tissue. The second is the white blood cells, which function as a deterrent to infection and has a role in the inflammatory process. The third is platelet. The platelet functions as a hemostatic sealant, scaffold for tissue regeneration, growth factor concentration, and stem cell binding.
In whole blood, platelets exist in a lower concentration, but in PRP, they exist in a much higher concentration as seen in these two photographs. In their resting state platelets exist as tiny discs individually, but when activated, they spill their proteins, which are growth factors or cytokines. These cytokines increase linearly with platelet concentration. What this means is that as the concentration increases, the number of growth factors increases proportionally. Growth factors signal transduction via the receptor tyrosine kinases. Growth factors have many roles. The stimulate chemotaxis, which is directional movement in response to a chemical stimulus. Stem cells are attracted to the growth factors and migrate into the area. Cell proliferation or cell division is a response to a stimulus by growth factors. Platelet signaling where growth factors bind to stem cell membrane and growth factor stimulates cell division.
The three primary benefits of PRP are stem cell binding, growth factor concentration, and tissue regeneration. Stem cells are stimulated to regenerate new tissue. The more growth factors released sequestered into the damaged cells, the more stem cells stimulated to produce new host tissue.
The growth factors in PRP include Epithelial Growth Factor, Fibroblast Growth Factor, Platelet-Derived Growth Factor, Transforming Growth Factor - Beta, Transforming Growth Factor- Alpha, Interleukin 1, and Vascular Endothelial Growth Factor (VEGF).
There have been over 30 growth factors identified in platelets thus far. The benefits of many of these growth factors are summarized below.
Stimulates re-epithelialization, angiogenesis, collagenase activity.
Stimulates angiogenesis, endothelial cell proliferation, collagen synthesis, and wound contracture. It also produces a keratinocyte growth factor.
Activates TGF-beta, stimulates neutrophils and macrophages, stimulates chemotaxis, stimulates mitogenesis of fibroblasts and smooth muscle cells, stimulates collagen synthesis and collagenase activity, and stimulates angiogenesis. PDGF is produced by alpha granules in the platelets.
Stimulates monocytes to secrete FGF, PDGF, Tumor Necrosis Factor-Alpha and interleukin-a, stimulates fibroblast chemotaxis and proliferation, a potent stimulator of collagen synthesis, reduces dermal scarring, promotes cell mitosis, significantly increases type I collagen production in tendon sheath fibroblast, and reverses the inhibition of wound healing caused by glucocorticoids. It is produced in alpha granules in the platelets.
Stimulates mesenchymal, epithelial, and endothelial cell growth stimulates endothelial chemotaxis and is a variant of Epithelial Growth Factor.
Stimulates lymphocyte proliferation and influences collagenase activity.
Important in wound healing and stimulates both proliferation and differentiated function in osteoblasts.
Stimulates angiogenesis or new blood vessel development. This is important is re-establishing blood supply to the new graft and increasing blood supply to the grafted area, as well as repairing vessels damaged during the hair transplant process.
As you can see, these growth factors are very important to the healing process. Concentrating the growth factors has been shown in numerous procedures to improve the outcome. Procedures that have thus far shown benefit include that Neurosurgery, Oral and Maxillofacial Surgery, Otorhinolaryngology- (head and neck surgery), Plastic Surgery, Urology, Periodontal Surgery, and Ortho/Spinal Surgery. The concentration of the growth factors seems to play a large role in why there has been documented benefit from the use of Platelet Rich Plasma (PRP). Just how much of an increase might you see? According to Eppley in 2004 Platelet Rich Plasma (PRP) increases growth factor concentration of PDGF, TGF-B, and VEGF are as follows:
1. PDGF 17 ng/ml (5 fold increase over whole blood)
2. VEGF 995 pg/ml (6 fold increase over whole blood)
3. TGF-B 42 ng/ml (3.6 fold increase over whole blood)
When discussing platelet-rich plasma (PRP) it is worthwhile to consider history. First, you must understand that it is derived from the patient's own blood, which means it is autologous so it is often referred to as Autologous Platelet Rich Plasma or (APRP). It was first developed in the early 1970s as a byproduct of multicomponent pheresis. The techniques and equipment for the production of platelet-rich plasma (PRP) have significantly improved through the 1990s and beyond. Over the years, the benefits of platelet-rich plasma (PRP) have been documented in many different surgical procedures as previously mentioned. It is only recently that platelet-rich plasma (PRP) was introduced for hair transplant surgery.
Originally, it was used in storage mediums for grafts. More recently it has been used to inject all layers of the recipient with concentrated growth factors. Lee et al have found that the use of platelet-rich plasma (PRP) speeds up the growth rate of grafts. They determined this by injecting one side with platelet-rich plasma (PRP) and comparing it to the growth rate on the opposite side where no platelet-rich plasma (PRP) was used. This study is still underway, however, and more data needs to be collected prior to drawing any firm conclusions on the benefits of PRP to the rate of resumed growth of transplanted hair.
Even more recently, Greco has used PRP to inject the hair on the top of the scalp that is undergoing miniaturization due to androgenic alopecia. He has found that PRP improves coverage in up to 75% of patients who undergo treatment with PRP.