Hair Follicle Stem Cells for Tissue Regeneration

Abstract

With the positive outcomes of various cell therapies currently under preclinical and clinical studies, there is a significant interest in novel stem cell sources with unique therapeutic properties. Studies over the past two decades or so demonstrated the feasibility to isolate multipotent/pluripotent stem cells from hair follicles. The easy accessibility, high proliferation, and differentiation ability as well as lack of ethical concerns associated with this stem cell source make hair follicle stem cells (HFSCs) attractive candidate for cell therapy and tissue engineering. This review discusses the various stem cell types identified in rodent and human hair follicles and ongoing studies on the potential use of HFSCs for skin, bone, cardiovascular, and nerve tissue engineering. Impact statement Hair follicle stem cells are an autologous stem cell source, and recent preclinical and clinical studies demonstrated its unique properties to support and accelerate tissue regeneration, making it an attractive candidate for cell therapy and tissue engineering.

Keywords: biomaterials; bone tissue engineering; cardiac tissue engineering; hair follicle stem cells; nerve tissue engineering; skin tissue engineering.

FIG. 1.

Schematic illustration of the menagerie of stem cells and their individual locations in the resting (telogen) adult hair follicle. The stem cell populations are depicted by their distinct gene/protein expression or promoter activity: Lgr5 (green, hair germ and bulge), CD34 (orange, bulge), LRC (yellow, bulge), Lgr6 (pink, lower isthmus), Lrig1/MTS24 (blue, isthmus), Blimp1 (violet, sebaceous gland opening), and K15* (a truncated version of the K15 promoter, restricted in its activity to the bulge area). IFE, interfollicular epidermis; LRC, label retaining cell. Color images are available online.