Both normal and transected olfactory axons have the unusual property of being able to grow into adult CNS, find their appropriate targets, and form synaptic contacts with them. A critical element in the ability of olfactory axons to regenerate and form specific connections is the presence of a unique supporting cell, the olfactory ensheathing glia
(OEG). These cells uniquely present both Schwann cell-like and astrocyte-like characteristics and seem to have great potential to repair damaged spinal cord. However, not all axonal populations grow into OEG implants. Additional vector-mediated neurotrophin expressed could enhance their regeneration-supporting properties, because endogenous neurotrophic factor expressed by OEG is low.