An autologous epidermal equivalent tissue-engineered from follicular outer root sheath keratinocytes is as effective as split-thickness skin autograft in recalcitrant vascular leg ulcers.

The outer root sheath of hair follicles plays an important role in epidermal regeneration in vivo. Keratinocytes isolated by explantation of outer root sheath tissue have extensive proliferative capacity irrespective of donor age, which probably depends on pluripotent epithelial stem cells residing in the outer root sheath. These keratinocytes can be organotypically grown to epidermal equivalents in vitro. We report here that in a multicenter, randomized phase II study, EpiDex(TM), a tissue-engineered, fully differentiated autologous epidermal equivalent derived from keratinocytes of the outer root sheath of plucked anagen hair follicles, is as effective as split-thickness skin autografting in the promotion of healing and complete closure of recalcitrant vascular leg ulcers.