Hair follicle bulge stem cells: A new source for skin regeneration

Emergence and spread of various diseases in the past century have been associated with many problems for the health care providers. Now a days، with advancement of technology، new methods such as cell therapy، are available، efficient and successful in some clinical areas. To use any cell، it is necessary to identify its source، so herein، we reviewed the literature of a new source of adult stem cells in the bulge of hair follicle. Hair is composed of two parts: root and shaft. Proximal two-thirds of the hair root، called hair follicle that is surrounded by two dermal and epidermal sheaths. Epidermal sheath included inner and outer root sheath. Outer root sheath at the junction of the errector pilli muscle and sebaceous glands make the bulge that includes stem cells. In this review we described anatomy of the hair follicle، hair growth cycle، hair follicle bulge، embryonic source of hair follicle، isolation of bulge stem cells using cell surface markers، gene expression and differentiation in bulge stem cells directing differentiation of bulge stem cells in normal skin repair، and practical advantages of bulge stem cells over other stem cells.