Topically applicable non-drug hair growth-promoting agents are of major medical and consumer interest. We have shown that stimulation of the olfactory receptor (OR), OR2AT4, by the odorant Sandalore®, prolongs human hair growth ex vivo, and slows hair loss in telogen effluvium patients in vivo. Here, we asked whether another OR, i.e. OR2A4/7, which promotes epidermal keratinocyte proliferation, unfolds similar properties. By in situ hybridization, ubiquitous OR2A4/7 mRNA expression was detected in the HF epithelium (outer root sheath [ORS], hair matrix [HM]) of freshly embedded scalp skin from healthy donors, whereas OR2A4/7 protein expression (IF) was almost restricted to the infundibulum. During HF organ culture, which induces tissue distress, OR2A4/7 protein expression was up-regulated also in the ORS and HM. When organ-cultured scalp HFs were treated with a cosmetically applicable OR2A4/7 agonist, the synthetic fragrance cyclohexyl salicylate (CHS), this resulted in delayed catagen development and tendentially increased HM keratinocyte proliferation. Most interestingly, the number of CD34+ cells and CD71+ transit amplifying cells, i.e. the immediate progeny of HF epithelial stem cells which is reduced in androgenetic alopecia, was significantly increased in the suprabulbar ORS/HM. Since stimulation of OR2A4/7 with CHS promoted human hair growth and expanded the progeny of HF epithelial stem cells ex vivo, this invites the exploration of CHS as a novel, fragrance-based adjunct treatment for hair loss disorders associated with telogen effluvium and/or reduced HF stem cell progeny expansion.

ESDR572 - Olfactory Receptor 2A4/7 Activation by the Fragrance, Cyclohexyl Salicylate, Promotes Human Hair Follicle Growth and Stem Cell Progeny Expansion

The scientific meeting of the European Society for Dermatological Research (ESDR) is held yearly, usually in September. With an international attendance of more than 1000 skin scientists from around the globe, the four-day event includes short oral presentations from peer-reviewed abstracts, keynote lectures from international experts, sponsored symposia, satellite programs, educational events as well as an important focus on posters, networking and building collaborations amongst scientists. For more information about this year’s meeting visit our website.