Partial Alopecia Area Retains Bulge Hair Follicle Progenitor Cells in Indian Androgenetic Alopecia Patients

ABSTRACT Background: Androgenic alopecia (AGA) is a pathological condition characterized by the progressive decrease of scalp hair follicle density. Completely bald areas of AGA scalp exhibit a drastically decreased number of progenitor cells. However, it is unknown when the progenitor cells begin to diminish in number during the progression of AGA. Despite the prevalence of AGA in 58% of the Indian male population, no study to date has characterized the hair follicle stem and progenitor cell populations in AGA patients in this ethnic group. Aims and Objective: In this study, we tested the presence of progenitor cells marked by CD34 and Sox9 in the partially and fully bald scalp of Indian AGA patients. Material and Methods: We utilized punch biopsies from the scalp of Indian AGA patients and quantified the status of hair follicle progenitor cells via histological and immunofluorescence analysis. Results: We observed that the partially bald area retains progenitor cells expressing CD34 and Sox9, but they are not present in the hair follicles in the completely bald area. Conclusion: Therapeutic interventions based on maintaining and activating hair follicle progenitor cells would be most effective at the partially bald stage of AGA.