Improvement of Nerve Regeneration in Tissue-Engineered Skin Enriched with Schwann Cells

The incorporation of Schwann cells in reconstructed skin (RS) could have a major role in achieving functional recovery of cutaneous sensory perception. We showed with a unique in vitro model of a tissue-engineered innervated reconstructed dermis that Schwann cells promoted a twofold increase in the number of sensory neurites migrating in the three-dimensional tissue as compared with the control. In addition, Schwann cells spontaneously colocalized along neurites and achieved the formation of myelin sheaths in vitro as assessed by transmission electron microscopy. We prepared RS samples enriched or not with Schwann cells and transplanted them on nude mice for 60-90 days. We demonstrated that Schwann cells induced a 1.8- and 1.7-fold increase in the number of nerve fibers migrating in the graft 60 and 90 days after transplantation, respectively. In addition, the RS sample enriched with Schwann cells had a current perception threshold similar to that of normal skin for the large and myelinated A beta-sensory fibers, in contrast with the control. Thus, we showed that the addition of Schwann cells to tissue-engineered skin not only enhanced nerve migration but also promoted myelin sheath formation in vitro and nerve function recovery in vivo.