Schwann cells, neurotrophic factors, and peripheral nerve regeneration

Abstract

The peripheral nervous system retains a considerable capacity for regeneration. However, functional recovery rarely returns to the preinjury level no matter how accurate the nerve repair is, and the more proximal the injury the worse the recovery. Among a variety of approaches being used to enhance peripheral nerve regeneration are the manipulation of Schwann cells and the use of neurotrophic factors. Such factors include, first, nerve growth factor (NGF) and the other recently identified members of the neurotrophin family, namely, brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), neurotrophin-4/5 (NT-4/5); second, the neurokines ciliary neurotrophic factor (CNTF) and leukemia inhibitory factor (LIF); and third, the transforming growth factors (TGFs)-beta and their distant relative, glial cell line-derived neurotrophic factor (GDNF). In this review article we focus on the roles in peripheral nerve regeneration of Schwann cells and of the neurotrophin family, CNTF and GDNF, and the relationship between these. Finally, we discuss what remains to be understood about the possible clinical use of neurotrophic factors.

Neurotrophic Factors and Neural Prostheses: Potential Clinical Applications Based Upon Findings in the Auditory System

“…Some cells, such as Schwann cells, are known to naturally produce small quantities of neurotrophic factors [95,96], and transplantation of these cells into the cochlea of deaf guinea pigs has demonstrated a small but significant protective effect on SGNs [97]. Alternatively, ex vivo gene transfer may lead to even greater survival effects.…”

Expression of neurotrophic factors by Schwann Cells promotes regeneration of central nervous system

“…It is possible that SC conditioned medium (SCCM) may promote neuronal development, survival or act as a neuronotrophic factor and attract a growing or regenerating axon down a myelin sheath. This finding, together with our previous report that SCCM contains an NGF-like molecule (Frostick, et al, 1998), supports the hypothesis that the SC synthesizes several target-specific neurotrophic factors (Assouline et al, 1987). Collier and Martin (1993) suggested that a diffusible product, or combination of products, derived from SC activated by nerve explantation, influences embryonic dopamine neurons to promote cell survival and neurite extension by these cells.…”

Bridging defects in chronic spinal cord injury using peripheral nerve grafts combined with a chitosan-laminin scaffold and enhancing regeneration through them by co-transplantation with bone-marrow-derived mesenchymal stem cells: Case series of 14 patients

“…Clinically, motor function significantly improved after re-implanting avulsed spinal roots directly to the ventral aspect of the spinal cord. 28 Before final closure of the dura, a chitosan scaffold containing laminin as a neurite outgrowth promoting factor 14,29,30 was applied before injecting the autologous stem cells (Fig. 1J).…”