**Hair Follicle Reconstruction and Stem Cells**

**Hair Follicle Reconstruction and Stem Cells**

Ekaterina P. Kalabusheva, Elina S. Chermnykh, Vasily V. Terskikh and Ekaterina A. Vorotelyak Elina S. Chermnykh, Vasily V. Terskikh and Ekaterina A. Vorotelyak

Additional information is available at the end of the chapter Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/66707

Ekaterina P. Kalabusheva,

#### **Abstract**

*De novo* hair follicle (HF) formation in embryonic skin and hair growth in postnatal skin are the result of epithelial-mesenchymal interactions between specialized mesenchymal dermal papilla (DP) and epithelial stem cells that give rise to hairs. Adult HF is a valuable source of different lineages of stem cells (SCs) with morphogenetic potential. Epithelial stem cells are residing in the special compartment of HF (the bulge) and can be mobilized to regenerate the new follicle with each hair cycle and to reepithelialize epidermis during wound repair. This review summarizes the current knowledge on key characteristics of HF SC populations in terms of regenerative potential. General biological principles that govern the mesenchymal-epithelial interactions within the HF and the signaling pathways that control HF development are discussed. The main focus is on recent approaches to reconstruct folliculogenesis *in vitro* and perspectives of the tissue engineering in alopecia therapy.

**Keywords:** epidermis, hair follicle, morphogenesis, stem cells, hair follicle reconstruction, dermal papilla

### **1. Introduction**

Alopecia is a growing health problem in the world, and the age of patients tends to decrease [1]. Dermatologists and trichologists have an increasing list of young patients including women, at the age of 25–30 years or even teenagers. At the same time, there are only few really effective remedies in the field. Achievements in cell biology and biotechnology propose novel products to solve these problems. One of the promising and reasonable ways to develop cell products for hair loss treatment is to obtain trichogenic cells and then to grow small folliclelike structures. To develop effective strategies of hair follicle (HF) reconstruction we need to

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

have a deep insight into cellular and molecular mechanisms of HF development and regeneration. The research on HF is a rapidly developing area of skin biology. This mini-organ can be successfully used for a wide range of studies into the mechanisms of morphogenesis, stem cell behavior, cell differentiation, and apoptosis [2–4]. Moreover, as mentioned above, HF investigations can provide invaluable insights into the possible causes of human hair disorders and provide conditions for development of HF restoration technologies.
