Alopecia and platelet-derived therapies.

Background: Platelet rich plasma (PRP) injections have emerged as a promising regenerative therapy for androgenetic alopecia (AGA). To date, injections of both autologous native and activated PRP have been administered to hair loss patients, and positive results have been observed. However, little to no work has yet to be seen wherein PRP treatments are combined with hair restoration surgeries. Furthermore, the PRP activation protocol in the hair restoration setting employs compounds with potentially deleterious side effects, namely thrombin or calcium gluconate. Therefore, the objectives of this work are to evaluate the effectiveness of platelet and platelet-derived products as augmented graft therapies in hair restoration surgeries and to compare the follicular regeneration rate of follicles transplanted in the presence of platelet lysate (PL) versus activated PRP (AA-PRP).

Methods: PL was administered to the frontal scalp of three male AGA patients. Three treatment zones measuring 4 cm were mapped in the midline scalp region of each patient and equal number of follicular grafts were placed in each box along with PL, AA-PRP, or normal saline. The transplanted follicular grafts of a fourth patient were placed solely with PL. Hair checks in which the surface area of hair coverage was quantified were performed at follow-up appointments ranging from 3.5 to 7 months post-surgery. In these appointments, the number of follicular units with hairs measuring 50 mm or more were counted to determine the percentage of graft hair regeneration. Growth factor (GF) concentrations [vascular endothelial growth factor (VEGF), transforming growth factor beta 1 (TGF-β1), PDGF-BB, IGF-1] in PL and AA-PRP were also measured for an independent subject set.

Results: Follicular regeneration in transplanted grafts was found to be superior for those placed with PL rather than AA-PRP or saline at all follow-up dates. Specifically, at 3.5 months post-op, 89%±9%, 74%±7%, and 57%±10% of follicular units had regenerated hair in the PL, AA-PRP, and saline treatment zones, respectively. At 4 months post-op, 99%, 75%, and 71% of follicle regeneration had occurred in the PL, AA-PRP, and saline treatment areas, respectively. Impressively, when PL was injected alone, the patient experienced a 50% increase in follicular unit density and a 122% increase in hair density 7 months post-injection. When GF concentrations were measured, PL generated from a 30-min sonication of PRP was found to have significantly higher levels of VEGF, PDGF-BB, and TGF-β1 than AA-PRP.

Conclusions: PRP remains a promising hair loss therapy and should be evaluated further for use not only as an independent therapeutic tool, but also as a treatment to augment surgical procedures. PL in particular affords an effective and efficacious therapeutic product given that the lysate may be obtained by mechanical rather than chemical means. Ultrasonic waves provide sufficient energy to rupture platelet cell walls, and centrifugation may be used to separate the lysate from cell fragments prior to delivery.