Table 1.

Advantages and Possible Challenges of In Vitro Hair Follicle Regeneration

Advantages
Controlled growth conditions with defined culture media and growth substrate (e.g., collagen gel)
Better manipulation of the heterogenic cell–cell and cell–matrix interactions necessary for trichogenesis by precise spatial arrangement (e.g., sandwiched gel culture)
Identification of specific exogenous stimuli relevant to folliculogenesis (e.g., hormones, growth factors, and vitamins)
Possible control of the size and density of neofollicles

Challenges
Restoration of the required epithelial–mesenchymal interactions for trichogenesis
Preservation of the proper responses of follicular cells to signals independent of native skin milieu and surrounding stroma
Maintenance of the trichogenic capacity in isolated follicle cells without juxtaposition to other cells and extracellular matrix
Creation of the concentric structure of hair follicles
Regeneration of complete hair follicles with a full capacity to form new hair shaft
Reestablishment of the normal hair growth cycle