The Utility of Platelet-Rich Plasma for the Treatment of Alopecia

July 2020 | Volume 19 | Issue 7 | Original Article | 736 | Copyright © July 2020


Published online June 12, 2020

Margit L.W. Juhasz MD MSc,a, Kristen Lo Sicco MDb, Jerry Shapiro MDb

aUniversity of California, Irvine, Department of Dermatology, Irvine, CA bNew York University, The Ronald O. Perelman Department of Dermatology, New York, NY

Abstract
Importance: Platelet-rich plasma (PRP) is a novel therapy for alopecia. Although the use of PRP remains under investigation, medical practitioners administer PRP for hair regrowth without quantitative evidence of clinical results.
Objective: Systematically review literature regarding PRP for alopecia.
Evidence Review: PRISMA guidelines were utilized to search the PubMed database in May 2019 with search terms “platelet rich plasma” and “hair”, “hair loss”, or “alopecia”. Manuscripts were included if they were written in English and described PRP treatment in human subjects with alopecia.
Findings: Sixty-one articles discussed the use of PRP as monotherapy, or in combination with other medical modalities, for the treatment of androgenetic alopecia (AGA), alopecia areata (AA), and cicatricial alopecia, ranging from level Ib to IV evidence. PRP results in significant increase in hair density and hair shaft width in AGA patients, with high rates of patient satisfaction and minimal adverse events. Data heterogeneity and limited number of well-designed, large-scale clinical trials were limitations of this review.
Conclusions and Relevance: Preliminary results regarding the use of PRP for AGA, AA, and cicatricial alopecias are promising. Physicians should be aware that current studies often report qualitative, rather than quantitative, clinical outcomes and should counsel patients regarding PRP treatment efficacy accordingly.

J Drugs Dermatol. 2020;19(7): doi:10.36849/JDD.2020.5192

INTRODUCTION

Platelet-rich plasma (PRP) is an autologous blood product consisting of platelet-derived growth factors and concentrated platelets 1.6 to 8-fold times physiologic levels. Platelets may be “activated” to release growth-factor (GF)-rich granules using calcium-based compounds, thrombin, and components of extracellular matrix.1 Due to PRP’s purported regenerative, anti-inflammatory and anti-bacterial properties, it is utilized for various medical conditions. In dermatology, PRP is promising for skin rejuvenation, chronic ulcers, and alopecia.

The Mechanism of PRP for Hair Regrowth
The exact mechanism for PRP-induced hair regrowth is unknown. Platelet-derived GFs include platelet-derived growth factor (PDGF), transforming growth factor (TGF)-β, vascular endothelial growth factor (VEGF), epithelial growth factor (EGF), and insulin-like growth factor (IGF). It is unclear whether platelet activation is required, or if the injection process is enough for GF release as both preparations result in therapeutic response.

GFs bind receptors on hair follicle bulge stem cells – PDGF causes keratinocyte proliferation and prolongs the anagen phase in mouse models, IGF-1 prevents induction of the catagen phase, fibroblast growth factor (FGF) promotes dermal papilla cell (DPC) proliferation and hair shaft elongation, while VEGF is implicated in hair follicle revascularization.2-5 Although it was hypothesized that PRP’s effects are dependent on GF plasma concentration,5,8 clinically significant results despite low GF concentrations contradict this theory.9 For instance, a clinical trial demonstrated that although two, commercially available, calcium-activated PRP kits had similar GF concentrations, one kit resulted in superior hair growth.1

Calcium chloride-activated PRP causes upregulation of mitogen-activated protein kinase (MAPK) and protein kinase B (Akt) signaling, as well as downregulation of glycogen synthase kinase-3 and Wnt pathways, all playing a role in hair growth.6,7 PRP increases expression of type I collagen and matrix metalloproteinase 1 mRNA in dermal fibroblasts. Upregulation of Bcl-2, an anti-apoptotic protein, allows for differentiation of hair follicle stem cells, while β-catenin and FGF-7 in dermal fibroblasts prolongs the anagen phase, and Ki-67 results in epidermal cell proliferation.10 PRP also contains fibrin, fibronectin, thrombin, vitronectin and cytokines [interferon (IFN)-α, interleukins (ILs)-4, 5, 13, 17, tumor necrosis factor (TNF)]; their role in hair regeneration is unknown.3