Autologous Micrografts Containing Nanovesicles, Exosomes, and Follicle Stem Cells in Androgenetic Alopecia: in Vitro and in Vivo Analysis Through a Multicentric, Observational, Evaluator-Blinded Study

The use of micrografts (MCGs) containing human follicle mesenchymal stem cells (HF-MSCs) is a hair loss (HL) treatment that needs to be standardized as seems to have promising effects on hair regrowth (HR-G) also thanks to the presence of extracellular vesicles (EVs). The study aims to report both the in vivo results, obtained in patients affected by androgenic alopecia (AGA) treated using MCGs, and in vitro analysis characterizing the EVs. A multicentric, retrospective, observational, evaluator-blinded study was conducted. Eighty-three AGA patients were initially enrolled [52 suffering from male pattern hair loss (MPHL) at stages I–III vertex by the Norwood–Hamilton scale and 31 suffering from female PHL (FPHL) at stages I–II by the Ludwig scale]. Sixty patients (20 females and 40 males) were treated and analyzed after exclusion and inclusion criteria assessment. The in vivo HR-G was evaluated through photography, physician’s, and patient’s global assessment scales, in addition to standardized photo-trichograms, during a follow-up for 1 year, while the in vitro analysis was performed through a quantitative, morphological, and dimensional characterization of the EVs population using transmission electron microscopy (TEM) and fluorescent microscopy. A hair density (HD) increase of 28 ± 4 hairs/cm2 at T4 after 12 months in the targeted area (TA) of FPHL, compared with the baseline, was observed using computerized trichograms with a statistically significant difference (SSD) in hair regrowth (HR-G) (p = 0.0429). Regarding MPHL, an HD increase of 30 ± 5 hairs/cm2 at T4 after 12 months in the TA was observed with an SSD in HR-G (p = 0.0012). The presence of EVs and their interaction with the surrounding cellular population were demonstrated. MCGs containing HF-MSCs and exosomes may fill in as a safe and viable alternative treatment against HL in mild and moderate degrees of AGA both in MPHL and in FPHL. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .