Adipose-derived stem cells protect against endoneurial cell death: Cell therapy for nerve autografts

Background One of the major problems with nerve grafts is that the survival of a graft segment, including endoneurial Schwann cells (SCs), is uncertain. We investigated whether the survival of nerve grafts is improved when adipose‐derived stem cells (ASCs) are incorporated into the grafts. Methods To examine the cell‐protective effects of ASCs on SCs in vitro, we used an indirect coculture system. In vivo effects of the incorporation of ASCs into grafts were examined using a graft model in the rat common peroneal nerve. Grafts were entubulated to isolate them from the surrounding tissues, mimicking the clinical conditions of a poorly vascularized recipient bed. Thirty‐six Lewis rats were divided into three groups, i.e., nerve graft only, entubulated nerve graft, and entubulated nerve graft + ASC transplantation. In each group, four rats and eight rats were used for short‐term (10 days) and long‐term (12 weeks) follow‐up study, respectively. Results After 24 hours of serum deprivation, the numbers of 7‐aminoactinomycin D, and TUNEL‐positive SCs significantly decreased when indirectly cocultured with ASCs (P