Exosomes: A New Effective Non-Surgical Therapy for Androgenetic Alopecia? Gupta Aditya K,Renaud Helen J,Halaas Yael,Rapaport Jeffrey A Skinmed Exosome therapy is a promising new approach for the treatment of hair loss. Current treatments for androgenetic alopecia, the most common form of hair loss, fall short of providing satisfactory efficacy with minimal side effects; thus, the fact that exosome therapy delivers impressive hair growth with no reported adverse events makes this therapy an attractive avenue to be explored; nevertheless, due to the novelty of this treatment, clinical trials to confirm its efficacy and safety are lacking. The current state of knowledge that is publicly available on the efficacy of exosome therapy for treatment of hair loss is reviewed, and the potential of exosomes as an alternate therapy for hair restoration is discussed.

Immunoregulatory Effects of Myeloid-Derived Suppressor Cell Exosomes in Mouse Model of Autoimmune Alopecia Areata. Zöller Margot,Zhao Kun,Kutlu Natalia,Bauer Nathalie,Provaznik Jan,Hackert Thilo,Schnölzer Martina Frontiers in immunology The treatment of autoimmune diseases still poses a major challenge, frequently relying on non-specific immunosuppressive drugs. Current efforts aim at reestablishing self tolerance using immune cells with suppressive activity like the regulatory T cells (Treg) or the myeloid-derived suppressor cells (MDSC). We have demonstrated therapeutic efficacy of MDSC in mouse Alopecia Areata (AA). In the same AA model, we now asked whether MDSC exosomes (MDSC-Exo) can replace MDSC. MDSC-Exo from bone marrow cells (BMC) cultures of healthy donors could substantially facilitate treatment. With knowledge on MDSC-Exo being limited, their suitability needs to be verified in advance. Protein marker profiles suggest comparability of BMC- to collected inflammatory MDSC/MDSC-Exo in mice with a chronic contact dermatitis, which is a therapeutic option in AA. Proteome analyses substantiated a large overlap of function-relevant molecules in MDSC and MDSC-Exo. Furthermore, MDSC-Exo are taken up by T cells, macrophages, NK, and most avidly by Treg and MDSC-Exo uptake exceeds binding of MDSC themselves. In AA mice, MDSC-Exo preferentially target skin-draining lymph nodes and cells in the vicinity of remnant hair follicles. MDSC-Exo uptake is accompanied by a strong increase in Treg, reduced T helper proliferation, mitigated cytotoxic activity, and a slight increase in lymphocyte apoptosis. Repeated MDSC-Exo application in florid AA prevented progression and sufficed for partial hair regrowth. Deep sequencing of lymphocyte mRNA from these mice revealed a significant increase in immunoregulatory mRNA, including FoxP3 and arginase 1. Downregulated mRNA was preferentially engaged in prohibiting T cell hyperreactivity. Taken together, proteome analysis provided important insights into potential MDSC-Exo activities, these Exo preferentially homing into AA-affected organs. Most importantly, changes in leukocyte mRNA seen after treatment of AA mice with MDSC-Exo sustainably supports the strong impact on the adaptive and the non-adaptive immune system, with Treg expansion being a dominant feature. Thus, MDSC-Exo could potentially serve as therapeutic agents in treating AA and other autoimmune diseases. 10.3389/fimmu.2018.01279