Quantitative proteomic analysis of dermal papilla from male androgenetic alopecia comparing before and after treatment with low‐level laser therapy

Background Currently, low‐level laser therapy (LLLT) has been approved as a new treatment for androgenetic alopecia (AGA). However, it has not been elucidated how LLLT promotes hair growth in vivo . Objectives To investigate the change in protein expression from dermal papilla (DP) tissues in male AGA patients after LLLT treatment using liquid chromatography tandem mass spectrometry (LC‐MS/MS) analysis. Methods This is an open‐label, prospective, single‐arm study obtained punch scalp biopsy specimens from patients with AGA before and after LLLT treatment. Each subject was self‐treated with helmet type of LLLT (655 nm, 5 mW) device at home for 25 minutes per treatment every other day for 24 weeks. LC‐MS/MS analysis based on the dimethyl labeling strategy for protein quantification was used to identify proteins expressed in DP tissues from AGA patients. Results Proteomic analysis revealed 11 statistically significant up‐regulated and 2 down‐regulated proteins in LLLT treated DP compared with baseline ( P < 0.05). A bioinformatic analysis signifies that these proteins are involved in several biological processes such as regulation of cellular transcription, protein biosynthesis, cell energy, lipid homeostasis, extracellular matrix (ECM), ECM structural constituent, cell‐cell/cell‐matrix adhesion as well as angiogenesis. ATP‐binding cassette sub‐family G member, a transporter involved in cellular lipid homeostasis, was the most up‐regulated protein. Additionally, LLLT increased the main ECM proteins in DP which results in a bigger volume of DP and a clinical improvement of hair diameter in AGA patients. Conclusion We identified the proteome set of DP proteins of male patients with AGA treated with LLLT which implicates the role of LLLT in promoting hair growth and reversing of miniaturization process of AGA by enhancing DP cell function. Our results strongly support the benefit of LLLT in the treatment of AGA. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.