Peripheral nerve repair with cultured schwann cells: getting closer to the clinics

Abstract

Peripheral nerve injuries are a frequent and disabling condition, which affects 13 to 23 per 100.000 persons each year. Severe cases, with structural disruption of the nerve, are associated with poor functional recovery. The experimental treatment using nerve grafts to replace damaged or shortened axons is limited by technical difficulties, invasiveness, and mediocre results. Other therapeutic choices include the adjunctive application of cultured Schwann cells and nerve conduits to guide axonal growth. The bone marrow is a rich source of mesenchymal cells, which can be differentiated in vitro into Schwann cells and subsequently engrafted into the damaged nerve. Alternatively, undifferentiated bone marrow mesenchymal cells can be associated with nerve conduits and afterward transplanted. Experimental studies provide evidence of functional, histological, and electromyographical improvement following transplantation of bone-marrow-derived cells in animal models of peripheral nerve injury. This paper focuses on this new therapeutic approach highlighting its direct translational and clinical utility in promoting regeneration of not only acute but perhaps also chronic cases of peripheral nerve damage.

Figure 1

Stem cell with scaffold support in peripheral nerve injury. (a) Nerve injury with stem cell transplantation shows limited remyelination and axonal growth between the proximal and distal stumps. (b) Nerve injury with scaffolding devices can be fabricated to secrete neurotrophic factors aiming to enhance the regenerative process, but still the outcome results in limited remyelination and axonal growth between the proximal and distal stumps. (c) The combined use of stem cells and scaffolding promotes best results, allowing an improved substrate for cell-to-cell contact and increased concentrations of released neurotrophic factors. Additionally, transplanted stem cells may stimulate endogenous Schwann cells to proliferate at a higher rate, thus enhancing remyelination and axonal growth following peripheral nerve damage.