Dermal Sheath Cells and Hair Follicle Regeneration

Abstract

The dermal sheath (DS) cells are present in a sheath-like connective tissue on the outermost side of the hair follicle; DS connects to the dermal papilla (DP) in the lower part of the hair bulb. The ability of DP cells to induce and regenerate hair follicles has been demonstrated in a great number of studies as discussed in other chapters. In this chapter, the characteristics and functions of DS cells in hair follicle regeneration have been reviewed. The potential of a clinical application using DS cells for male and female pattern loss is also discussed in this chapter. The PubMed database was used for the selection of papers with keywords including ‘dermal sheath’, ‘connective tissue sheath’, and ‘hair’. Through a comprehensive reading of the abstracts, papers on hair follicle regeneration were further selected and cited. Several papers have shown that DS cells can induce growth of new hair follicles. Recent studies reported the presence of hair follicle dermal stem cells in the DS, suggesting these may be responsible for hair follicle regeneration. Based on these properties, clinical studies have been conducted on male and female pattern hair loss using lower DS cells. The initial results from these studies show safety and some efficacy of lower DS cells in hair follicle regeneration. In conclusion, several rodent studies have shown that the DS and cells derived from it have both hair regenerative and skin regenerative potential. Further studies characterizing human DS cells and identifying if there are human hair follicle dermal stem cells need to precede further understanding of human hair follicle regeneration, for the development of an efficient clinical application for male and female pattern hair loss.KeywordsHair folliclesDermal sheathConnective tissue sheathAndrogenetic alopeciaCell-based therapy