The potential for using growth factors to promote healing and hair growth after hair transplantation is centered in three functional applications:
Between the time that hair follicles are removed from a donor area of the scalp and transplanted into a recipient area, they are subject to damage from several causes:
A common approach to maintaining donor hair follicle viability during the transition period is to keep them in a storage solution that provides a protective environment of appropriate temperature, chemical balance and nutrient supply. Recent research has indicated that addition of PRP to the storage solution improves follicle viability during and after transplantation, enhances post-transplantation tissue healing and promotes hair growth in transplanted follicles. An approach advocated by some investigators is to bathe the donor hair follicles in activated PRP just prior to transplantation.
Investigators have reported that PRP promotes hair growth from follicles by the action of platelet growth factors on hair follicle stem cells. The platelet growth factors induce follicle stem cells to shift from a dormant state to an active state that starts the process of hair production.
In activity promoting tissue repair and healing after injury of surgery, the growth factors stored in platelets are released at a site of tissue injury, promoting tissue repair and healing. Individual growth factors such as PDGF have been used by surgeons to promote wound healing in hospitalized surgical patients. The rationale for using PRP in outpatient surgical hair restoration is to use the full array of platelet-associated growth factors to promote healing and minimize scar formation, as well as to promote maximum hair growth in transplanted follicles.
After noting enhanced hair growth of transplanted hair after use of PRP, investigators conducted a small study of PRP effect on dormant non-transplanted hair follicles. The study hypothesized that platelet growth factors can “wake up” dormant hair follicles and begin the production of new hair. PRP was applied after scalp skin was slightly injured to induce platelets to release growth factors at the injury site. Enhanced hair growth and hair diameter was noted over the next 4 months, with a fall-off in enhanced hair growth after 4 months.