Platelet-derived extracellular vesicles promote hair follicle growth through β-catenin signaling pathway.

The application of platelet concentrates such as platelet-rich plasma (PRP) for the treatment of hair loss is impeded by the absence of standardized preparation protocols and storage conditions. Providing off-the-shelf controlled product methods and inheriting regenerative function of platelets, platelet-derived extracellular vesicles (PEVs) can be a promising alternative to surpass platelet concentrates limitations. This study aimed to investigate the effects of PEVs on cultured dermal papilla cells (DPCs) and hair follicles (HFs) in animal model. PEVs were prepared from fresh apheresis platelets and characterized. Their impact on the proliferation and migration of DPCs was explored. After subcutaneous administration of PEVs in a mouse model of depilation-induced hair regeneration, we observed the accelerated transition of HFs from the telogen to the anagen phase, and found the β-catenin signaling pathway was involved. These results indicate that PEVs activate DPCs and promote HF growth effectively. The PEVs from apheresis platelets offer a robust alternative for the treatment of hair loss.