In Vitro Skin Models to Study Epithelial Regeneration from the Hair Follicle

The study investigated the ability of intact pilosebaceous units (PSU) and truncated hair follicles (THF) to regenerate a multilayered epidermis in vitro using de-epidermalized dermis (DED) and collagen-glycosaminoglycan (C-GAG) dermal equivalents. It was found that PSU were more effective than THF in forming a multilayered epidermis in DED. Both DED and C-GAG expressed various markers related to proliferation, differentiation, and stem cells. Although neither PSU nor THF formed a multilayered epidermis in C-GAG in vitro, hair follicles implanted into engrafted C-GAG on a burns patient resulted in epithelial regeneration, indicating that in vivo factors were crucial for full epidermal regeneration with C-GAG. The study highlighted the potential of DEs, particularly PSU, as models for studying hair follicle progenitor epithelial cells during epidermal regeneration.