Rapid innervation and physiological epidermal regeneration by bioengineered dermis implanted in mouse.

Tissue-engineered skin substitutes are promising tools to cover large and deep skin defects. However, the lack of a synergic and fast regeneration of the vascular network, nerves, and skin appendages limits complete skin healing and impairs functional recovery. It has been highlighted that an ideal skin substitute should mimic the structure of the native tissue to enhance clinical effectiveness. Here, we produced a pre-vascularized dermis (PVD) comprised of fibroblasts embedded in their own extracellular matrix (ECM) and a capillary-like network. Upon implantation in a mouse full-thickness skin defect model, we observed a very early innervation of the graft in 2 weeks. In addition, mouse capillaries and complete epithelialization were detectable as early as 1 week after implantation and, skin appendages developed in 2 weeks. These anatomical features underlie the interaction with the skin nerves, thus providing a further cue for reinnervation guidance. Further, the graft displays mechanical properties, collagen density, and assembly features very similar to the host tissue. Taken together our data show that the pre-existing ECM components of the PVD, physiologically organized and assembled similarly to the native tissue, support a rapid regeneration of dermal tissue. Therefore, our results suggest a promising potential for PVD in skin regeneration.