Generation of Pigmented Skin Grafts from Human Hair Follicles and Dermal Fibroblasts.

Skin equivalents are able to mimic key features of human skin and they can be used for a very broad range of applications, such as fundamental studies of skin biology, disease, and toxicological models, as well as an alternative for animal testing. The high end of their use is in therapy of wound healing and repigmentation and disorders that massively affect individual health as well as quality of life and pose considerable burden to health care systems worldwide. Tissue-engineered skin grafts often originate from invasively obtained cell material (i.e., biopsy). Hereby, an unmet need for noninvasively gained autologous biological starting material has been created. The hair follicle, entirely noninvasively available by plucking, harbors a heterogeneous cell pool, including stem cells with an immense differentiation capacity, hereby representing an attractive source of cells, especially for purposes of regenerative medicine. In this study, we engineered three-dimensional pigmented epidermal and dermoepidermal grafts using human keratinocytes and melanocytes from the outer root sheath of hair follicles combined with dermal fibroblasts. The grafts were generally anatomically correct and functional regarding stratification and formation of epidermal melanin units, as well as extracellular matrix deposition, exhibiting moderate differences to the skin anatomy and function, typical for the