Maximizing the Use of Autologous Platelet Rich Plasma in Hair Transplantation Surgery

Joseph Greco, PhD, PA/C, Robert J. Brandt

Abstract
The primary use for platelet rich plasma (PRP) in hair restoration surgery has demonstrated an increased yield when utilized as a graft storage medium.  When bathed in activated PRP the growth factors attach to the stem cells in the bulge area of the dissected follicular unit, thus increasing the yield of newly transplanted follicles.( Uebel, 2005) 1
The author’s suggest expanding the use of PRP in hair restoration surgery for the following reasons: (1) to enhance donor site wound healing, (2) to decrease the incidence of infection, (3) to reduce donor scaring, (4) to increase donor scar tensile strength (5) to enhance recipient site healing and (6) to be utilized as an effective treatment protocol in severe cases of wound dehiscence or infection. In addition to the PRP (7) platelet poor plasma (PPP) has potent sealant properties that can be utilized for hemostasis during the procedure.
Discussion
Platelet derived growth factor (PDGF) is the evolutionary sentinel growth factor that initiates all wound healing. Platelet rich plasma (PRP) contains several growth factors, including platelet-derived growth factors (PDGF) and transforming growth factor-beta (TGF-beta 1) at high levels and vascular endothelial growth factor (VEGF). 

Growth factors are present in the bulge area, where stem cells are found, and they interact with cells of the matrix, thus activating the proliferative phase of the hair. Stem cells are more primitive and of ectodermal origin; they give origin to the epidermal cells and the sebaceous glands. Cells of the dermal papilla, which are found at the capillary base, are of mesenchymal origin. Both cells need each other, and when they interact through the action of various growth factors they will give rise to the future follicular unit.
Platelet derived growth factors' main functions are to stimulate cell replication (mitogenesis) of healing capable stem cells. It also stimulates cell replication of endothelial cells. This will cause budding of new capillaries into the wound (angiogenesis), a fundamental part of all wound healing. In addition, PDGF seems to promote the migration of perivascular healing capable cells into a wound and to modulate the effects of other growth factors. Numerous studies and practical applications have also demonstrated how growth factors are essential for regulating the cellular events involved in wound healing by attracting cells to the wound, stimulating proliferation, and significantly influencing matrix deposition. (Declare, 1999) 2
TGF-beta is extremely important because it affects most aspects of tissue wound repair, namely initiation and termination and also promotes differentiation and proliferation ( Chio and Fuchs, 1990) 3.  PDGF improves dermal regeneration, acts locally to promote protein and collagen synthesis, causes endothelial migration or angiogenesis (Ross, 1987) 4 and induces the expression of TGF-beta (Pierce et al., 1989) 5.
It was further established that wounds treated with PRP gel exhibited not only enhanced wound repair compared to control, but possess more organized collagen than control tissues, without excessive disposition of connective tissue or scar formation (Carter, et al., 2002) 6. This equine study by Carter et al demonstrated biopsy wounds treated with PRP gel to be densely organized, tightly packed fiber bundles parallel to the overlying epidermis suggesting the dense collagen lattice had increased tensile strength in the repaired wound.

Fig 1, bottom right slide.

Method
 The use of PDGF in surgery is widely documented and has become standard intra-operative and post-operative protocol to promote hemostasis, accelerate wound healing and decrease the incidence of wound infection.
It is therefore suggested that PRP gel is an excellent protocol for donor wound closures. After the subcuticular layer is closed with 3.0 Monocryl, activated PRP gel is injected into the wound from end to end (Fig 2) and the second layer is approximated with a running 3.0 Prolene suture. After utilizing PRP gel in the donor site wounds appear to bleed less post- operatively than those not treated with PRP.

Fig 2

After the follicular units are dissected, they are bathed in activated PRP gel (PRP can be activated with calcium chloride/ thrombin or fibrinogen and becomes a gel like substance) approximately 15 mins prior to implantation so the growth factors can attach to the stem cells in the bulge region of the dissected follicular units.
While dissection is ongoing and the graft design pattern is completed the PRP is then injected into the recipient scalp area after the graft pattern is completed to maximize the multiple effects of growth factors. The PRP providesan enriched environment of concentrated growth factors to accelerate the wound response thus promoting healing and angiogenesis for the newly implanted follicular units. See Fig 3 below.

Fig 3   

Injecting PRP into the recipient area may have other advantages for the non transplanted hairs since platelet rich plasma (PRP) contains several growth factors, including platelet-derived growth factors (PDGF) and vascular endothelial growth factor (VEGF). (Takakura et al, 1996) 7 demonstrated that PDGF signals are involved in both epidermis-follicle interaction and the dermal mesenchyme interaction required for hair canal formation and the growth of dermal mesenchyme, respectively. In  2001, ( Yano et al) 8 identified VEGF as a major mediator of hair follicle growth and cycling providing the first direct evidence that the improved follicle vascularization promotes hair growth and increases follicle and hair size.
In 2003, the co-author, Robert Brandt, demonstrated rapid healing and hair re-growth utilizing PRP on a severely traumatized wound in an equine model. While it generally takes nine months for a wound such as this to heal, if the animal survives, (Fig 2, 3, 4) below demonstrates the wound and healing process after PRP was utilized. (Fig 2) shows a totally open wound without tissue extending deep to the bone. (Fig 3) illustrates the rapid healing of the wound at one week, but (Fig 4) demonstrates complete wound closure and hair re-growing at one month, which never occurs in these cases. Enlarged photos can be seen at the web site http://bloodrecovery.com/wound_ba2.htm

Fig 2	Fig 3	Fig 4
Before	One Week	One Month

This equine case is a significant example of the extraordinary effects that PRP has on rapid wound repair and hair re-growth in especially difficult cases. It illustrates yet another very valuable use for PRP, especially, in cases of severe infection or wound dehiscence. Rapid use of PRP in this instance, can not only promote healing of the infected wound, but will also promote the re-growth of hair thus avoiding possible impending scaring traumatic alopecia.

Fig 5	Fig 6	Fig7
Before	7 Days	12 Days

This author has observed a more rapid healing after injecting PRP into the recipient site in hair transplantation. Based on the previously mentioned studies regarding the effects growth factors have on hair growth studies are planned to test the effects PRP and growth factors have on the non-transplanted hair. 
 Fear of liner donor scaring and complications gave rise to patient popularity of follicular unit extraction (FUE). The use of platelet rich plasma for donor wound healing is an answer for both patients and physicians concerns regarding scarring and donor site aesthetics in the most natural cost effective way.
In the final analysis, in addition to its use as a graft storage medium this author proposes multiple uses of PRP in hair transplantation to include, but not be limited to 1- enhanced donor wound healing, 2- decreased donor scarring, 3- increased donor wound tensile strength, 4- increased bactericidal properties, 5- enhanced recipient area healing and 6- be utilized as an effective treatment protocol in severe cases of wound dehiscence or infection. In addition to the PRP 7- platelet poor plasma (PPP) has potent sealant properties that can be utilized for hemostasis during the procedure.

References