Efficacy and Safety of Platelet-Rich Plasma Therapy in Alopecia Areata Patients: A Systematic Review

Table 3

Mechanisms proposed for platelet-rich plasma (PRP) in the treatment of alopecia areata (AA).

General hair growth	Growth factors	PRP contains various growth factors, including platelet-derived growth factor (PDGF), transforming growth factor-beta (TGF-β), vascular endothelial growth factor (VEGF), and insulin-like growth factor (IGF). These growth factors play a crucial role in promoting hair follicle growth, proliferation, and differentiation [41, 42].
	Angiogenesis stimulation	PRP stimulates angiogenesis, the formation of new blood vessels. Improved blood supply to the hair follicles enhances nutrient and oxygen delivery, providing an optimal environment for hair growth and follicular regeneration [41].
	Stem cell activation	PRP contains bioactive substances that help activate and recruit dormant hair follicle stem cells. These stem cells have the potential to differentiate into hair follicle cells, promoting hair growth and regeneration [43].
	Extracellular matrix remodeling	PRP modulates the extracellular matrix, which provides structural support to the hair follicles. This remodeling process helps improve the hair follicle’s anchoring ability, leading to stronger and healthier hair growth [44].
Autoimmune AA	Immunomodulation	PRP exhibits immunomodulatory properties by regulating the immune response and suppressing inflammatory processes. This modulation helps to reduce the autoimmune attack on hair follicles in AA [45].
	Anti-inflammatory effects	The growth factors and cytokines present in PRP possess anti-inflammatory properties. By mitigating the inflammatory response, PRP helps to alleviate the destructive impact of inflammation on hair follicles in AA [46].
	Wound healing and Tissue repair	PRP’s regenerative properties aid in wound healing and tissue repair. This can be beneficial in repairing the damaged hair follicles and promoting a favorable environment for hair regrowth [47].